Research Contributions
@sub{Dugan_Fourier_SD,
author={Jordan Dugan and Tom J. Smy and Shulabh Gupta},
journal={IEEE Transactions on Antennas and Propagation},
title={Mixed Spatial-Spectral Domain Representation of Higher-Order Electromagnetic Boundary Conditions},
year={2024},
}
@sub{Smith_biPCBFelx,
author={Francis Baccin-Smith and Jose Epstein and Shulabh Gupta},
journal={IEEE Antennas Wirel. Propag. Lett.},
title={Ultrathin Flexible Bi-directional Leaky-Wave Antennas for use in the Wi-fi Band},
year={2024},
}
@sub{Smith_biPCB,
author={Francis Baccin-Smith and Mohamed K. Emara and Shulabh Gupta},
journal={IEEE Transactions on Antennas and Propagation},
title={Bi-directional Leaky-Wave Antennas (LWAs) with Independent Beam Scanning Laws},
year={2024},
}
@sub{Sakyi_WG_Floquet,
author={Papa Sakyi and Jordan Dugan and Debidas Kundu and Tom J. Smy and Shulabh Gupta},
journal={IEEE Transactions on Antennas and Propagation},
title={Waveguide-Floquet Mapping Using Surface Susceptibilities for Passive and Active Metasurface Unit Cell Characterization},
year={2024},
}
@ARTICLE{nizer_FDTD_SD,
author={Rahmeier, Joao Guilherme Nizer and Dugan, Jordan and Smy, Tom J. and Gupta, Shulabh},
journal={IEEE Access},
title={Time-Domain Analysis of Temporally and Spatially Dispersive Metasurfaces in GSTC-FDTD Frameworks},
year={2024},
volume={12},
number={},
pages={22557-22572},
keywords={Dispersion;Metasurfaces;Time-domain analysis;Finite difference methods;Mathematical models;Surface waves;Magnetic susceptibility;Electromagnetics;Lorentz covariance;Reflection coefficient;Electromagnetic metasurfaces;electromagnetic propagation;finite-difference timedomain;generalized sheet transition conditions (GSTCs);Lorentz oscillator model;spatial dispersion;spatial frequency domain;surface susceptibility tensors},
doi={10.1109/ACCESS.2024.3364518}}
@sub{Dugan_SD_synt,
author={Jordan Dugan and Tom J. Smy and Francesco Monticone and Shulabh Gupta},
journal={IEEE Transactions on Antennas and Propagation},
title={Surface Susceptibility Synthesis of Spatially Dispersive Metasurfaces for Space Compression and Spatial Signal Processing},
year={2023},
}
@ARTICLE{10320319,
author={Emara, Mohamed K. and Kundu, Debidas and Macdonell, Keigan and Rufail, Leandro M. and Gupta, Shulabh},
journal={IEEE Access},
title={Dynamic Metasurface Reflectors Based on Coupled Resonators for Simultaneous Magnitude and Phase Control},
year={2023},
volume={11},
number={},
pages={129552-129565},
doi={10.1109/ACCESS.2023.3333869}}
@ARTICLE{Wnag_IFR,
author={Wang, Kan and Smy, Tom J. and Gupta, Shulabh},
journal={IEEE Antennas and Wireless Propagation Letters},
title={Experimental Demonstration of the Incident Field Reconstruction Method for Metasurface Characterization},
year={2024},
volume={23},
number={3},
pages={910-914},
keywords={Antenna measurements;Horn antennas;Probes;Surface waves;Surface reconstruction;Antenna arrays;Time measurement;Gaussian beams;incident field reconstruction (IFR);near-field scanning;probe correction;uniform plane waves (PWs);metasurface (MS) characterization},
doi={10.1109/LAWP.2023.3334203}}
@sub{Keigan_Ref,
author={Keigan Macdonell and Debidas Kundu and Colin Andersen and Leandro Rufail and Shulabh Gupta},
journal={IEEE Transactions on Antennas and Propagation},
title={A Mechatronic Shape-shifting Reflector System with True Independent Reflection Magnitude and Phase Control for Dynamic Beamforming},
year={2023},
}
@article{Emara_segmented,
author = {Emara, Mohamed K. and Gupta, Shulabh},
title = {A segmented periodic slot array leaky-wave antenna for beamforming applications},
journal = {Microwave and Optical Technology Letters},
volume = {66},
number = {2},
pages = {e34072},
keywords = {beamforming, flat-top beam, leaky-wave antenna, millimeter-wave band, side-lobe level reduction, substrate-integrated waveguide, suppressed broadside stopband},
doi = {https://doi.org/10.1002/mop.34072},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/mop.34072},
eprint = {https://onlinelibrary.wiley.com/doi/pdf/10.1002/mop.34072},
abstract = {Abstract A segmented periodic slot array leaky-wave antenna (LWA) is proposed for beamforming applications. The LWA consists of N \$N\$ segments, each with a unique propagation constant achieved through varying periodicity and slot size. By using segments with different propagation constants, the proposed LWA can achieve beamforming such as flat-top beams and side-lobe level (SLL) reduction. The LWA is based on a substrate-integrated waveguide with periodic double transverse slots in the broad wall of the waveguide. The double slots allow for reflection-canceling to suppress the broadside stopband and hence can achieve beamforming capabilities in the backward, broadside, and forward directions. Full-wave simulations are used to demonstrate the proposed concept for flat-top beamforming in the mm-wave band at 30 GHz. Experimental demonstration is conducted using two prototypes for flat-top beams and SLL reduction, with good agreement with full-wave simulations.},
year = {2024}
}
@sub{Emara_RA_Dynamic,
author={Mohamed K. Emara and Debidas Kundu and Keigan Macdonell and Leandro Rufail and Shulabh Gupta},
journal={IEEE Transactions on Antennas and Propagation},
title={Reconfigurable Metasurface Reflectors Using Split-Ring Resonators with Co-Designed Biasing for Magnitude/Phase Control},
year={2023},
}
@sub{Kan_contactless_AWPL,
author={Kan Wang and Mohamed K. Emara and Tom J. Smy and Shulabh Gupta},
journal={Microw. Opt. Technol. Lett.},
title={Pattern Reconfigurable mm-Wave Leaky-Wave Antenna Array Using Contactless Excitation},
year={2024},
}
@ARTICLE{10171997,
author={Dugan, Jordan and Rahmeier, João G. Nizer and Smy, Tom J. and Gupta, Shulabh},
journal={IEEE Antennas and Wireless Propagation Letters},
title={Field Scattering Analysis of Cylindrical Spatially Dispersive Metasurfaces},
year={2023},
volume={22},
number={11},
pages={2619-2623},
doi={10.1109/LAWP.2023.3291868}}
@ARTICLE{Emara_RA,
author={Emara, Mohamed K. and Kundu, Debidas and Macdonell, Keigan and Rufail, Leandro M. and Gupta, Shulabh},
journal={IEEE Transactions on Antennas and Propagation},
title={Coupled Resonator-Based Metasurface Reflector With Enhanced Magnitude and Phase Coverage},
year={2024},
volume={72},
number={1},
pages={901-914},
keywords={Metasurfaces;Resonators;Reflectivity;Array signal processing;Resonant frequency;Encoding;Substrates;Anomalous reflection;beamforming;complex reflectance;coupled resonators;effective surface susceptibilities;Lorentz oscillators;metasurface absorbers;metasurface reflectors;multibeam generation},
doi={10.1109/TAP.2023.3332436}}
@inproceedings{Rajan_Sas,
author={Feng Su and David Luong and Ian Lam and Sreeraman Rajan and Shulabh Gupta},
journal={IEEE Sensor Applications Symposium 2023},
title={Machine Learning-Based Real-time Metasurface
Reconfiguration},
year={2023},
}
@inproceedings{Dugan3Meta2023,
author={J. Dugan and T. J. Smy and S. Gupta},
journal={13th International Conference on Metamaterials, Photonic Crystals and Plasmonics},
title={Non-Uniform Array of Polarizable Particles as a Locally Linear Space Invariant (LSI) Metasurface},
year={2023},
}
@inproceedings{Dugan2Meta2023,
author={J. Dugan and T. J. Smy and F. Monticone and S. Gupta},
journal={13th International Conference on Metamaterials, Photonic Crystals and Plasmonics},
title={Surface Susceptibility Synthesis of Spatially Dispersive Metasurfaces},
year={2023},
}
@inproceedings{DuganMeta2023,
author={J. Dugan and T. J. Smy and S. Gupta},
journal={13th International Conference on Metamaterials, Photonic Crystals and Plasmonics},
title={Extended Surface Susceptibility Model of Electromagnetic Metasurfaces for Microscopic Field Determination},
year={2023},
}
@inproceedings{Gupta_URSIGA2023,
author={S. Gupta and K. MacDonell and T. Tomura and J. Hirokawa},
journal={XXXVth General Assembly and Scientific Symposium of the International Union of Radio Science (URSI-GA)},
title={160 GHz Millimeter-wave Huygens Beam-forming Transmit Arrays for Fixed Radio Link Communication Systems},
year={2023},
}
@inproceedings{Debi2_URSIGA2023,
author={Debidas Kundu and S. Gupta},
journal={XXXVth General Assembly and Scientific Symposium of the International Union of Radio Science (URSI-GA)},
title={A 1-Bit Coding Reconfigurable Metasurface Reflectarray for Beam Steering of Circularly Polarized Wave from a Linearly Polarized Incidence},
year={2023},
}
@inproceedings{Emara_URSIGA2023,
author={M. K. Emara and L. M. Rufail and S. Gupta},
journal={XXXVth General Assembly and Scientific Symposium of the International Union of Radio Science (URSI-GA)},
title={Coupled Resonator Metasurface Supercell for Independent Control of Orthogonal Polarizations with Enhanced Complex Reflectance},
year={2023},
}
@inproceedings{Keigan_URSIGA2023,
author={K. MacDonell and D. Kundu and L. M. Rufail and S. Gupta},
journal={XXXVth General Assembly and Scientific Symposium of the International Union of Radio Science (URSI-GA)},
title={Mechatronic Shape-Shifting Reflector Platform for Dynamic Beam-steering},
year={2023},
}
@inproceedings{Smy_URSIGA2023,
author={T. J. Smy and S. Gupta},
journal={XXXVth General Assembly and Scientific Symposium of the International Union of Radio Science (URSI-GA)},
title={Modified Generalized Sheet Transition Conditions for Modeling Thick Metasurfaces},
year={2023},
}
@inproceedings{Debi_URSIGA2023,
author={D.Kundu and M.K.Emara and L.M.Rufail and S.Gupta},
journal={XXXVth General Assembly and Scientific Symposium of the International Union of Radio Science (URSI-GA)},
title={Waveguide-Floquet Mapping Based on Surface Susceptibilities for Metasurface Unit Cell Characterization},
year={2023},
}
@sub{Murto_CombRampart,
author={Tomi Murto and Joseph Epstein and Shulabh Gupta},
journal={Microw. Opt. Technol. Lett.},
title={Conformal and Flexible Leaky-Wave Combline Antenna Arrays},
year={2024},
}
@ARTICLE{10124139,
author={Dugan, Jordan and Rahmeier, João Guilherme Nizer and Smy, Tom J. and Gupta, Shulabh},
journal={IEEE Transactions on Antennas and Propagation},
title={Spatially Dispersive Metasurfaces—Part III: Zero-Thickness Modeling of Periodic and Finite Nonuniform Surfaces},
year={2023},
volume={71},
number={7},
pages={5935-5945},
doi={10.1109/TAP.2023.3274300}}
@ARTICLE{10109685,
author={Kundu, Debidas and Parameswaran, Aparna and Sonalikar, Hrishikesh Shashikant and Bhattacharya, Dhrubajyoti and Gupta, Shulabh},
journal={IEEE Transactions on Antennas and Propagation},
title={A Low-RCS Circularly Polarized Reflectarray Antenna With a Linearly Polarized Feed},
year={2023},
volume={71},
number={8},
pages={6501-6512},
doi={10.1109/TAP.2023.3269149}}
@ARTICLE{10153989,
author={Emara, Mohamed K. and Tomura, Takashi and Hirokawa, Jiro and Gupta, Shulabh},
journal={IEEE Transactions on Antennas and Propagation},
title={Metallo-Dielectric Millimeter-Wave Huygens’ Quarter-Wave and Half-Wave Plates},
year={2023},
volume={71},
number={8},
pages={6678-6687},
doi={10.1109/TAP.2023.3285112}}
@ARTICLE{10036354,
author={Smy, Tom J. and Stewart, Scott A. and Gupta, Shulabh},
journal={IEEE Transactions on Microwave Theory and Techniques},
title={Eigenfunction Expansion (EFE) Analysis of Cylindrical Metasurfaces—Part I: Zero Thickness Tensorial Surface Susceptibility Model},
year={2023},
volume={71},
number={8},
pages={3352-3365},
doi={10.1109/TMTT.2023.3240461}}
@ARTICLE{10036356,
author={Smy, Tom J. and Gupta, Shulabh},
journal={IEEE Transactions on Microwave Theory and Techniques},
title={Eigenfunction Expansion (EFE) Analysis of Cylindrical Metasurfaces—Part II: Sectors and Multishells},
year={2023},
volume={71},
number={8},
pages={3366-3378},
doi={10.1109/TMTT.2023.3240418}}
@ARTICLE{9751381,
author={Smy, Tom J. and Rahmeier, João G. Nizer and Dugan, Jordan and Gupta, Shulabh},
journal={IEEE Transactions on Antennas and Propagation},
title={Spatially Dispersive Metasurfaces—Part II: IE-GSTC-SD Field Solver With Extended GSTCs},
year={2023},
volume={71},
number={7},
pages={5920-5934},
doi={10.1109/TAP.2022.3164125}}
@ARTICLE{9751380,
author={Rahmeier, João Guilherme Nizer and Smy, Tom J. and Dugan, Jordan and Gupta, Shulabh},
journal={IEEE Transactions on Antennas and Propagation},
title={Zero Thickness Surface Susceptibilities and Extended GSTCs—Part I: Spatially Dispersive Metasurfaces},
year={2023},
volume={71},
number={7},
pages={5909-5919},
doi={10.1109/TAP.2022.3164169}}
@ARTICLE{10041015,
author={Demetre, Joel S. and Smy, Tom J. and Gupta, Shulabh},
journal={IEEE Transactions on Antennas and Propagation},
title={Static Metasurface Reflectors With Independent Magnitude and Phase Control Using Coupled Resonator Configuration},
year={2023},
volume={71},
number={4},
pages={3536-3545},
doi={10.1109/TAP.2023.3242076}}
@ARTICLE{10012304,
author={King, Daniel J. and Hettak, Khelifa and Chaharmir, Mohammad Reza and Gupta, Shulabh},
journal={IEEE Transactions on Components, Packaging and Manufacturing Technology},
title={Flexible Ink-Minimized Screen-Printed Frequency Selective Surfaces With Increased Optical Transparency for 5G Electromagnetic Interference Mitigation},
year={2023},
volume={13},
number={1},
pages={110-119},
month = {1},
doi={10.1109/TCPMT.2023.3235616}}
@article{Tiukuvaara2022,
abstract = {While metasurfaces (MSs) are constructed from deeply subwavelength unit cells, they are generally electrically large and full-wave simulations of the complete structure are computationally expensive. Thus, to reduce this high computational cost, nonuniform MSs can be modeled as zero-thickness boundaries, with sheets of electric and magnetic polarizations related to the fields by surface susceptibilities and the generalized sheet transition conditions (GSTCs). While these two-sided boundary conditions (BCs) have been extensively studied for single sheets of resonant particles, it has not been shown if they can correctly model structures where the two sides are electrically isolated, such as a fully reflective surface. In particular, we consider in this work whether the fields scattered from a fully reflective MS can be correctly predicted for arbitrary field illuminations, with the source placed on either side of the surface. In the process, we also show the mapping of a perfect electric conductor (PEC) sheet with a dielectric cover layer to bianisoptropic susceptibilities. Finally, we demonstrate the use of the susceptibilities as compact models for use in various simulation techniques, with an illustrative example of a parabolic reflector, for which the scattered fields are correctly computed using an integral-equation (IE)-based solver.},
author = {Ville Tiukuvaara and Tom J. Smy and Karim Achouri and Shulabh Gupta},
doi = {10.1109/TAP.2022.3184477},
issn = {0018-926X},
issue = {11},
journal = {IEEE Transactions on Antennas and Propagation},
keywords = {Boundary element methods (BEMs),electromagnetic metasurfaces (MSs),electromagnetic propagation,generalized sheet transition conditions (GSTCs)},
month = {11},
pages = {10583-10591},
title = {Surface Susceptibilities as Characteristic Models of Reflective Metasurfaces},
volume = {70},
url = {https://ieeexplore.ieee.org/document/9806373/},
year = {2022},
}
@article{Stewart2022,
abstract = {A ray optical methodology based on the uniform theory of diffraction (UTD) is proposed to model electromagnetic (EM) field scattering from curved metasurfaces (MSs). The problem addressed is the illumination of a purely reflective uniform cylindrical MS by a line source, models the surface with susceptibilities and employs a methodology previously used for cylinders coated in thin dielectric layers [Kim and Wang (1989)]. The approach is fundamentally based on a representation of the MS using the generalized sheet transition conditions (GSTCs) which characterizes the surface in terms of susceptibility dyadics. An eigenfunction (EF) description of the MS problem is derived considering both tangential and normal surface susceptibilities, and used to develop a ray optics (RO) description of the scattered fields including the specular geometrical optical field, surface diffraction described by creeping waves and a transition region over the shadow boundary. The specification of the fields in the transition region is dependent on the evaluation of the Pekeris caret function integral and the method follows [Kim and Wang (1989)]. The proposed RO-GSTC model is then successfully demonstrated for a variety of cases and is independently verified using a rigorous EF solution (EF-GSTC) and full-wave Integral Equation method (IE-GSTC), over the entire domain from the deep lit to deep shadow.},
author = {Scott Stewart and Tom J. Smy and Shulabh Gupta},
doi = {10.1109/TAP.2022.3184540},
issn = {0018-926X},
issue = {10},
journal = {IEEE Transactions on Antennas and Propagation},
keywords = {Creeping waves,cylindrical metasurface,electromagnetic (EM) metasurfaces (MSs),generalized sheet transition conditions (GSTCs),high-frequency methods,periodic structures,uniform theory of diffraction (UTD)},
month = {10},
pages = {9662-9676},
title = {Ray Optical Scattering From Uniform Reflective Cylindrical Metasurfaces Using Surface Susceptibility Tensors},
volume = {70},
url = {https://ieeexplore.ieee.org/document/9806046/},
year = {2022},
}
@article{Dugan2022,
abstract = {An accelerated integral equations (IE) field solver for determining scattered fields from electrically large electromagnetic metasurfaces using fast multipole method (FMM) is proposed and demonstrated in 2-D. In the proposed method, practical general metasurfaces are expressed using an equivalent zero thickness sheet model described using surface susceptibilities, and where the total fields around it satisfy the generalized sheet transition conditions (GSTCs). While the standard IE-GSTC offers fast field computation compared with other numerical methods, it is still computationally demanding when solving electrically large problems, with a large number of unknowns. Here, we accelerate the IE-GSTC method using the FMM technique by dividing the current elements on the metasurface into near-and far-groups, where either the rigorous or approximated Green's function is used, respectively, to reduce the computation time without losing solution accuracy. Using numerical examples, the speed improvement of the FMM IE-GSTC method \{O(N3/2)\} over the standard IE-GSTC \{O(N3)\} method is confirmed. Finally, the usefulness of FMM IE-GSTC is demonstrated by applying it to solve electromagnetic propagation inside an electrically large radio environment with strategically placed metasurfaces to improve signal coverage in blind areas, where a standard IE-GSTC solver would require prohibitively large computational resources and long simulation times.},
author = {Jordan Dugan and Tom J. Smy and Shulabh Gupta},
doi = {10.1109/TAP.2022.3177549},
issn = {0018-926X},
issue = {10},
journal = {IEEE Transactions on Antennas and Propagation},
keywords = {Boundary element method (BEM),electromagnetic metasurfaces,electromagnetic propagation,fast multipole method (FMM),generalized sheet transition conditions (GSTCs),radio environment engineering,surface susceptibility tensors},
month = {10},
pages = {9524-9533},
title = {Accelerated IE-GSTC Solver for Large-Scale Metasurface Field Scattering Problems Using Fast Multipole Method (FMM)},
volume = {70},
url = {https://ieeexplore.ieee.org/document/9785426/},
year = {2022},
}
@article{Smy2022,
abstract = {An integral equation (IE)-based electromagnetic field solver using metasurface susceptibility tensors is proposed and validated using a variety of numerical examples in 2-D. The proposed method solves for fields generated by the metasurface, which is represented as spatial discontinuities satisfying the generalized sheet transition conditions (GSTCs), and described using tensorial surface susceptibility densities, χ. For the first time, the complete tensorial representation of susceptibilities is incorporated in this integrated IE-GSTC framework, where the normal surface polarizabilities and their spatial derivatives along the metasurface are rigorously taken into account. The proposed field equation formulation further utilizes a local coordinate system, which enables modeling metasurfaces with arbitrary orientations and geometries. The proposed 2-D boundary element method BEM-GSTC framework is successfully tested using a variety of examples, including infinite and finite-sized metasurfaces, periodic metasurfaces, and complex shaped structures, showing comparisons with both analytical results and a commercial full-wave solver. It is shown that the zero-thickness sheet model with complete tensorial susceptibilities can very accurately reproduce the macroscopic fields, accounting for their angular field scattering response and the edge diffraction effects in finite-sized surfaces.},
author = {Tom J. Smy and Ville Tiukuvaara and Shulabh Gupta},
doi = {10.1109/TAP.2022.3142294},
issn = {0018-926X},
issue = {6},
journal = {IEEE Transactions on Antennas and Propagation},
keywords = {Boundary element methods (BEMs),Floquet analysis,electromagnetic (EM) metasurfaces,electromagnetic propagation,generalized sheet transition conditions (GSTCs),surface susceptibility tensors},
month = {6},
pages = {4752-4765},
title = {IE-GSTC Metasurface Field Solver Using Surface Susceptibility Tensors With Normal Polarizabilities},
volume = {70},
url = {https://ieeexplore.ieee.org/document/9686634/},
year = {2022},
}
@article{Tiukuvaara2022,
abstract = {Metasurfaces (MSs) are the 2-D equivalent of metaterials, the latter being a class of artificial engineered materials exhibiting peculiar electromagnetic properties [1], [2]. Generally constructed as arrays of deeply sub-wavelength resonant particles on a substrate, the geometry of the particles can be carefully designed to produce transformations of incident waves, including control of phase, amplitude, polarization, and direction of propagation. Recently, a major research direction has been the "intelligent" Metasurface (MS), where the wave transformation can be electrically controlled, which could be a viable means of achieving, in 5G and future wireless communications, the goal of manipulating and optimizing the propagation environment [3] or to even create sophisticated illusions and holograms on the fly [4]. Other topics that have recently been studied are surfaces with time-varying properties [5] and surfaces composed of particles with multipolar moments [6].},
author = {Ville Tiukuvaara and Kan Wang and Tom J. Smy and Shulabh Gupta},
doi = {10.1109/MIM.2022.9693444},
issn = {1094-6969},
issue = {1},
journal = {IEEE Instrumentation & Measurement Magazine},
month = {2},
pages = {69-75},
title = {Metasurface Near-Field Measurements with Incident Field Reconstruction Using a Single Horn Antenna},
volume = {25},
url = {https://ieeexplore.ieee.org/document/9693444/},
year = {2022},
}
@article{Stewart2022,
abstract = {This work continues the development of the ray-tracing method of de Jong (2021) for computing the scattered fields from metasurfaces characterized by locally periodic reflection and transmission coefficients. In this work, instead of describing the metasurface in terms of scattering coefficients that depend on the incidence direction, its scattering behavior is characterized by the surface susceptibility tensors that appear in the generalized sheet transition conditions (GSTCs). As the latter quantities are constitutive parameters, they do not depend on the incident field and, thus, enable a more compact and physically motivated description of the surface. The locally periodic susceptibility profile is expanded into a Fourier series subject to a spatially varying phase parameter, and the GSTCs are rewritten in a form that enables them to be numerically solved for the reflected and transmitted surface fields. The phase parameter can either be determined from a prescribed surface transformation or extracted from known surface susceptibilities. A method for the extraction of this phase parameter from a susceptibility profile using a spatial variant of the short-time Fourier transform (STFT) is proposed. The scattered field at arbitrary detector locations is constructed by evaluating critical-point contributions of the first and second kinds using a forward ray-tracing (FRT) scheme. The accuracy of the resulting framework has been verified with an integral equation-based boundary element method (BEM)-GSTC full-wave solver for a variety of examples, such as a periodically modulated metasurface, a metasurface diffuser, and a beam collimator.},
author = {Scott Stewart and Yvo L. C. de Jong and Tom J. Smy and Shulabh Gupta},
doi = {10.1109/TAP.2021.3111665},
issn = {0018-926X},
issue = {2},
journal = {IEEE Transactions on Antennas and Propagation},
keywords = {Electromagnetic (EM) metasurfaces,Generalized sheet transition conditions (GSTCs),High-frequency methods,Periodic structures,Short-time Fourier Transformation,Uniform theory of diffraction (UTD)},
month = {2},
pages = {1265-1278},
title = {Ray-Optical Evaluation of Scattering From Electrically Large Metasurfaces Characterized by Locally Periodic Surface Susceptibilities},
volume = {70},
url = {https://ieeexplore.ieee.org/document/9540248/},
year = {2022},
}
@inproceedings{Tiukuvaara2022,
abstract = {In this work, we consider the question: can a zero-thickness susceptibility model in conjunction with the generalized sheet transition conditions (GSTCs) be used to model impenetrable, fully-reflective metasurfaces (MSs)? Considering a simple case of a ground plane with a dielectric coating - for which the reflection is analytically known - we find a set of susceptibilities which only depends on the geometrical and electrical properties of the structure and is able to predict the scattering response regardless of the TE-polarized incident fields, with both forward and backward illumination.},
author = {V. Tiukuvaara and S. Gupta and Tom J. Smy and O. J. F. Martin and K. Achouri},
doi = {10.1109/Metamaterials54993.2022.9920831},
isbn = {978-1-6654-6584-7},
journal = {2022 Sixteenth International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials)},
month = {9},
pages = {X-454-X-456},
publisher = {IEEE},
title = {Dipolar GSTCs at an Impenetrable Boundary},
url = {https://ieeexplore.ieee.org/document/9920831/},
year = {2022},
}
@inproceedings{Rufail2022,
abstract = {A novel supercell concept is proposed to control the amplitude and phase of a metasurface reflector, independently for the two orthogonal polarizations, and is numerically demonstrated. The supercell concept is based on a fundamental unit cell that operates on one linear polarization only, which when spatially rotated by 90°, can be used to respond to the other orthogonal polarization. By spatially combining the unit cell and its spatially rotated version, a super cell is formed which can impart a desired reflection amplitude/phase to each of the polarizations without affecting the other.},
author = {Leandro M. Rufail and Mohamed K. Emara and Ahmed Z. Ashoor and Shulabh Gupta},
doi = {10.1109/AP-S/USNC-URSI47032.2022.9887209},
isbn = {978-1-6654-9658-2},
journal = {2022 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting (AP-S/URSI)},
month = {7},
pages = {1880-1881},
publisher = {IEEE},
title = {Metasurface Reflector with Independent Polarizations Control using a Supercell Concept},
url = {https://ieeexplore.ieee.org/document/9887209/},
year = {2022},
}
@inproceedings{Smy2022,
abstract = {A rigorous semi-analytical method to compute the scattered fields off a zero-thickness cylindrical metasurface (MS) is presented, which is described using complete tensorial surface susceptibilities, including both tangential and normal components. Exploiting the angular periodicities of the susceptibilities and the scattered fields in the Generalized Sheet Transition Conditions (GSTC), the scattered fields can be efficiently computed. Two examples of a purely reflective cylinder and a finite-sized arc are shown to demonstrate the proposed method.},
author = {Tom J. Smy and Scott A. Stewart and Joao G. Nizer Rahmeier and Shulabh Gupta},
doi = {10.1109/AP-S/USNC-URSI47032.2022.9886180},
isbn = {978-1-6654-9658-2},
journal = {2022 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting (AP-S/URSI)},
month = {7},
pages = {459-460},
publisher = {IEEE},
title = {Eigenfunction Analysis of Cylindrical Metasurfaces with Complete Tensorial Surface Susceptibilities},
url = {https://ieeexplore.ieee.org/document/9886180/},
year = {2022},
}
@inproceedings{,
abstract = {A bi-directional periodic leaky-wave antenna (LWA) is presented for the millimeter-wave (mm-wave) band with suppressed stopband and independent beam-scanning laws for top and bottom sides of the antenna, respectively. The bi-directional slot-pair antenna is designed to radiate out-of-plane beams along two directions on each antenna face. The operation of this antenna is verified using full-wave simulations at a design frequency of 28 GHz. The antenna can be engineered to point high gain beam along specified angles, and can be adapted to provide precision control of the independent output beams in various frequency bands.},
author = {Francis Baccin-Smith and Mohamed K. Emara and Shulabh Gupta},
doi = {10.1109/AP-S/USNC-URSI47032.2022.9887240},
isbn = {978-1-6654-9658-2},
journal = {2022 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting (AP-S/URSI)},
keywords = {bidirectional radiation,leaky-wave antennas,millimeter-wave,suppressed stopband},
month = {7},
pages = {1444-1445},
publisher = {IEEE},
title = {Bi-directional Leaky-Wave Antennas with Independent Beam-Scanning Laws},
url = {https://ieeexplore.ieee.org/document/9887240/},
year = {2022},
}
@inproceedings{Macdonell2022,
abstract = {A simple concept to perfectly decouple the reflection magnitude and phase of a reflective metasurface is proposed. For a linearly-polarized illumination, a full 2π phase is achieved in reflection by physically displacing the unit cell normal to the surface, with respect to a fixed reference and source, while the reflection magnitude is independently controlled via an integrated resistive element inside the unit cell. This proposed concept is demonstrated using full-wave simulations, which is the first step towards an electromechanical metasurface with truly independent real-time amplitude and phase control.},
author = {Keigan Macdonell and Leandro M. Rufail and Shulabh Gupta},
doi = {10.1109/AP-S/USNC-URSI47032.2022.9887317},
isbn = {978-1-6654-9658-2},
journal = {2022 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting (AP-S/URSI)},
month = {7},
pages = {29-30},
publisher = {IEEE},
title = {Concept of Independent Reflection Magnitude and Phase Using an Electromechanical Metasurface},
url = {https://ieeexplore.ieee.org/document/9887317/},
year = {2022},
}
@inproceedings{Rahmeier2022,
abstract = {A general polynomial expansion of the tangential susceptibilities with respect to the transverse wave-vector, k|| is presented to properly describe a spatially dispersive zero thickness model of an all-dielectric metasurface via an extended form of the generalized sheet transition conditions. Tangential susceptibilities of a typical cylindrical dielectric puck are extracted from commercial full-wave simulators and expanded into multi-Lorentz spatial resonances. Results are validated using integral equations solvers and show that ignoring spatial dispersion deprecates the metasurface field scattering response under oblique incidence.},
author = {Joao G. Nizer Rahmeier and Tom J. Smy and Shulabh Gupta},
doi = {10.1109/AP-S/USNC-URSI47032.2022.9886401},
isbn = {978-1-6654-9658-2},
journal = {2022 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting (AP-S/URSI)},
month = {7},
pages = {1508-1509},
publisher = {IEEE},
title = {Spatially Dispersive Zero Thickness Sheet Model of All-Dielectric Metasurfaces},
url = {https://ieeexplore.ieee.org/document/9886401/},
year = {2022},
}
@inproceedings{Emara2022,
abstract = {Two different bidirectional periodic leaky-wave an-tennas (LWAs) are presented for the millimeter-wave (mm-wave) band with suppressed stopbands and orthogonal radiation di-rections: a bidirectional side-fire antenna with left/right in-plane radiation and a bidirectional slot-pair antenna with top/bottom out-of-plane radiation. The operations of these antennas are con-firmed using full-wave simulations, with a broadside frequency of approximately 28 GHz. These antennas can be individually engineered to form various radiation patterns in each of their radiation planes, and can further be combined to design a tetra-directional periodic LWA.},
author = {M.K. Emara and S. Gupta},
isbn = {9788831299046},
journal = {2022 16th European Conference on Antennas and Propagation, EuCAP 2022},
keywords = {bidirectional radiation,millimeter-wave band,periodic leaky-wave antenna,suppressed stopband,tetra-directional radiation},
title = {Bidirectional Periodic Leaky-Wave Antennas Using Side-Fire and Slot-Pair Configurations},
year = {2022},
}
@inproceedings{Dugan2022,
abstract = {This paper presents and compares two methods for modeling spatially dispersive metasurfaces as zero thickness sheets. In the first method, the standard Generalized Sheet Transition Conditions (GSTCs) are expanded to account for multipolar surface current densities. The extra terms in the current expansion allow for additional surface susceptibilities to be included which relate the multipolar components to the average fields and their spatial derivatives. The second method accounts for spatial dispersion by expressing the dipolar surface susceptibilities as complex rational polynomial functions of the transverse wave vector k_\{Vert\}. This yields a set of differential equations relating the field differences across the surface to the average fields at the surface, leading to an extended form of the standard GSTCs. The two methods are then compared, and the multipolar modeling method is shown to be a subset of the extended GSTC method for the case of a uniform surface.},
author = {J. Dugan and J.G.N. Rahmeier and T.J. Smy and S. Gupta},
isbn = {9788831299046},
journal = {2022 16th European Conference on Antennas and Propagation, EuCAP 2022},
title = {Spatially Dispersive Electromagnetic Metasurfaces: Multipolar Modeling vs Extended GSTCs},
year = {2022},
}
@inproceedings{Dugan2022,
abstract = {An accelerated Integral Equations (IE) field solver for determining scattered fields from electrically large electromagnetic metasurfaces, with both normal and tangential susceptibilities, utilizing Fast Multipole Method (FMM) is proposed and demonstrated in 2D. In the proposed method, practical general metasurfaces are modeled as a zero thickness sheet model described with surface susceptibilities, and where the total fields around it satisfy the Generalized Sheet Transition Conditions (GSTCs). While the standard IE-GSTC offers fast field computation compared to other numerical methods, it is still computationally demanding when solving electrically large problems, with a large number of unknowns. Here we accelerate the IE-GSTC method using the FMM technique. Using a numerical example, the speed improvement of the FMM IE-GSTC method left\{ \{Oleft(\{\{N\{3/2\}\}\} right)\} right\} over the standard IE-GSTC \{left\{Oleft(N\{3\}right)right\}\} method is confirmed, when both tangential and normal surface susceptibilities are present.},
author = {J. Dugan and T.J. Smy and S. Gupta},
isbn = {9788831299046},
journal = {2022 16th European Conference on Antennas and Propagation, EuCAP 2022},
title = {FMM IE-GSTC Simulation of Metasurfaces with Complete Dyadic Surface Susceptibilities},
year = {2022},
}
@inproceedings{Emara2022,
abstract = {This paper investigates material and scattering loss from a general two-port leaky-wave antenna (LWA) in transmit and receive modes using scattering parameters. It is demonstrated that the total material and scattering losses depend on the LWA orientation and whether the LWA is used as a transmitter or a receiver, leading to a different radio frequency (RF) environment in each scenario. First, full-wave simulations are used to demonstrate this behavior for a patch-to-horn configuration. Then the behavior is experimentally demonstrated for two-port LWAs in different orientations with respect to a horn antenna.},
author = {M.K. Emara and S. Gupta},
isbn = {9788831299046},
journal = {2022 16th European Conference on Antennas and Propagation, EuCAP 2022},
keywords = {antenna loss,antenna measurements,antenna scattering,reciprocity,transmit and receive leaky-wave antenna},
title = {Investigation of Material and Scattering Losses in Antennas in Transmitting and Receiving Mode},
year = {2022},
}
@article{Tiukuvaara2021,
abstract = {A rigorous semianalytical Floquet analysis is proposed for modeling space-time-modulated metasurface and determining the scattered fields in terms of their harmonic components. The proposed method is based on generalized sheet transition conditions (GSTCs) treating a metasurface as a spatial discontinuity with zero thickness. The metasurface is described in terms of Lorentzian electric and magnetic surface susceptibilities, both tangential and normal to the surface, with parameters (e.g., resonant frequency) that are periodically modulated in both space and time. The unknown scattered fields are expressed in terms of Floquet harmonics, for which the amplitudes can be found by numerically solving a set of linear equations, leading to the total scattered fields. Using existing computational techniques and a commercial full-wave solver, the method is validated using several examples of pure-space and pure-time modulation with different modulation strengths and pumping frequencies. Finally, two cases of space-time modulation (standing wave perturbation and a traveling-wave perturbation) are presented to demonstrate the breaking of Lorentz reciprocity. The proposed method is simple and versatile and able to determine the steady-state response of a space-time-modulated metasurface that is excited with an oblique plane wave or a general incident field such as a Gaussian beam.},
author = {Ville Tiukuvaara and Tom J. Smy and Shulabh Gupta},
doi = {10.1109/TAP.2021.3070718},
issn = {0018-926X},
issue = {11},
journal = {IEEE Transactions on Antennas and Propagation},
keywords = {Electromagnetic metasurfaces,Floquet analysis,Lorentz dispersions,electromagnetic propagation,generalized sheet transition conditions (GSTCs),parametric systems},
month = {11},
pages = {7667-7678},
title = {Floquet Analysis of Space-Time Modulated Metasurfaces With Lorentz Dispersion},
volume = {69},
url = {https://ieeexplore.ieee.org/document/9399243/},
year = {2021},
}
@article{King2021,
abstract = {An analog, low-profile and shielded spectrum analyzer is proposed for operation at mm-wave frequencies around the 60 GHz band based on a novel side-fire leaky-wave antenna (LWA) configuration. The proposed side-fire periodic LWA is systematically developed from a conventional three-port waveguide T-junction which is modified to a LWA unit cell with an internal matching mechanism to suppress the stopband and enable broadside radiation based on unit cell symmetry considerations. The resulting periodic side-fire antenna radiates in the plane of the antenna, whereby the leakage power can either be allowed to radiate in free-space or kept confined inside a parallel-plate waveguide (PPW) structure. The proposed side-fire structure can therefore be completely shielded, making it useful as a broadband spectrum analyzer that is compatible with substrate-integrated waveguide (SIW) technology. Furthermore, a convex side-fire antenna is demonstrated to focus the radiated beams in the near-field of the structure to make the entire system compact. The integrated spectrum analyzer is experimentally demonstrated between 59 and 66 GHz providing 1 GHz frequency resolution. Furthermore, a simple mathematical model consisting of an array of line sources is used to efficiently model the beam-scanning characteristics of the curved side-fire LWA in the near-field of the structure.},
author = {Daniel J. King and Mohamed K. Emara and Shulabh Gupta},
doi = {10.1109/TAP.2021.3060893},
issn = {0018-926X},
issue = {9},
journal = {IEEE Transactions on Antennas and Propagation},
keywords = {5G systems,beam-scanning,conformal antennas,leaky-wave antennas (LWAs),near-field focusing,side-fire antennas,spectrum analysis,stopband suppression,substrate integrated waveguides (SIWs)},
month = {9},
pages = {5401-5412},
title = {Millimeter-Wave Integrated Side-Fire Leaky-Wave Antenna and Its Application as a Spectrum Analyzer},
volume = {69},
url = {https://ieeexplore.ieee.org/document/9364849/},
year = {2021},
}
@article{Emara2021,
abstract = {A novel application of leaky-wave antennas (LWAs) as multiplexers/demultiplexers is proposed and experimentally demonstrated in the millimeter-waveband at 60 GHz. The first application is demultiplexing of an oblique-incident free-space wideband plane wave into 2N channels using N LWAs with different beam-scanning laws. The second application is N -channel multiplexing and demultiplexing using N pairs of identical LWAs in each other's far-field, where each LWA pair is designed such that the broadside frequency is the center frequency of its respective channel. The Friis transmission equation is first used to analytically demonstrate the two applications. The LWAs are then implemented using reflection-canceling slot pairs using substrate integrated waveguide technology. The two applications are demonstrated in full-wave simulations and experimentally by conducting horn-to-LWA and LWA-to-LWA transmission measurements. The proposed LWAs provide a simple, compact, and high-efficiency multiplexing/demultiplexing solution with high-integration capability with other circuitry. Compared with conventional multiplexers, LWAs do not require matching networks and can be directly scaled to higher frequencies using the same architecture.},
author = {Mohamed K. Emara and Shulabh Gupta},
doi = {10.1109/TAP.2021.3060138},
issn = {0018-926X},
issue = {9},
journal = {IEEE Transactions on Antennas and Propagation},
keywords = {5G communication,demultiplexer,diplexer/duplexer,frequency discriminator,leaky-wave antenna (LWA),millimeter-wave (mm-wave),multiplexer,slot array antenna,stopband suppression,substrate integrated waveguide (SIW)},
month = {9},
pages = {5244-5256},
title = {Integrated Multiport Leaky-Wave Antenna Multiplexer/Demultiplexer System for Millimeter-Wave Communication},
volume = {69},
url = {https://ieeexplore.ieee.org/document/9362224/},
year = {2021},
}
@article{Rahmeier2021,
abstract = {A comprehensive treatment on complex eigenmodes is presented for general lossy traveling-wave electromagnetic structures. The per unit length propagation phase shift ( \beta )-dependent complex eigenfrequencies \Omega (\beta) are mapped to frequency-dependent complex propagation constant \gamma (\omega \{0\}) for a variety of electromagnetic structures. Rigorous procedures are presented to compute the complex eigenmodes of both uniform and periodic electromagnetic structures, confirmed using full-wave simulations and known analytical results. We further present two mapping procedures for arbitrary uniform and periodic structures, where the known \\{\Omega \{-\}\beta \\} relationship is expressed using rational polynomial expansions. Consequently, replacing \\{\Omega,~j\beta \\} with \\{\omega \{0\}, \gamma \\} in the known \\{\Omega \{-\}\beta \\} relation, a characteristic equation is formed, which is then numerically solved for the propagation constant \gamma , representing the physical dispersion relation \omega \{0\}(\beta) and the frequency-dependent attenuation relation \alpha (\omega \{0\}) of the structure. The mapping procedure is demonstrated for a variety of cases, including an unbounded uniform media, a rectangular waveguide, a Drude dispersive metamaterial, a biased ferrite medium, a periodic dielectric stack, and a periodic rectangular waveguide. The exact propagation characteristics have been successfully retrieved in all cases across both passbands and stopbands across frequency.},
author = {Joao G. Nizer Rahmeier and Ville Tiukuvaara and Shulabh Gupta},
doi = {10.1109/TAP.2021.3060083},
issn = {0018-926X},
issue = {8},
journal = {IEEE Transactions on Antennas and Propagation},
keywords = {Complex eigenmodes,eigenmodes analysis,lossy electromagnetic structures,metamaterials,periodic structures},
month = {8},
pages = {4644-4656},
title = {Complex Eigenmodes and Eigenfrequencies in Electromagnetics},
volume = {69},
url = {https://ieeexplore.ieee.org/document/9362191/},
year = {2021},
}
@article{Sakurai2021,
abstract = {A novel Huygens' transmit array (TA) is proposed based on a coupled-resonator approach to demonstrate millimeter-wave (mm-Wave) beamforming for linear polarization. The proposed structure is simple and compatible with standard printed circuit board (PCB) processes and utilizes a single dielectric substrate only. It is shown that by engineering the geometrical dimensions of the resonator, its electric (even-mode) and magnetic (odd-mode) resonances are excited in a balanced manner to achieve zero backscattering in a large bandwidth. This operation principle of the proposed Huygens' cell is explained in detail using both an insightful equivalent circuit model, as well as full-wave eigenmode analysis. Next, the proposed Huygens' cell is placed on top of a high-gain 2-D slot-array antenna, in its near field, to engineer its aperture field distribution. Several TA prototypes designed around the 60 GHz frequency band are demonstrated and experimentally characterized in both their near and far fields, to achieve difference pattern generation, beam expansion, and beam steering as application examples, in addition to a uniform surface demonstrating its low-loss performance.},
author = {Soichi Sakurai and Joao G. Nizer Rahmeier and Takashi Tomura and Jiro Hirokawa and Shulabh Gupta},
doi = {10.1109/TAP.2020.3030972},
issn = {0018-926X},
issue = {5},
journal = {IEEE Transactions on Antennas and Propagation},
keywords = {Beamforming,Huygens' structures,electromagnetic metasurfaces,millimeter waves (mm-Waves),slot-array antennas,transmit arrays (TAs)},
month = {5},
pages = {2686-2696},
title = {Millimeter-Wave Huygens’ Transmit Arrays Based on Coupled Metallic Resonators},
volume = {69},
url = {https://ieeexplore.ieee.org/document/9234045/},
year = {2021},
}
@inproceedings{Tomura2021,
abstract = {In parallel-fed waveguide slot array antennas, it is difficult to control the excitation phase of each element due to the complexity of the structure. A dielectric resonator-based transmit array, which can be loaded on antennas and whose excitation phase can be controlled, has been developed and evaluated. However, it requires drilling or laser processing, and fabrication error and productivity are issues. Transmit arrays based on printed circuit board (PCB) processing technology have been proposed, but they are narrow bandwidth and multilayer structures. In this paper, we present a transmit array using a single layer of PCB, and report on its design and measurement results.},
author = {Takashi Tomura and Soichi Sakurai and Jiro Hirokawa and Shulabh Gupta},
doi = {10.1109/iWEM53379.2021.9790685},
isbn = {978-1-6654-1828-7},
journal = {2021 IEEE International Workshop on Electromagnetics: Applications and Student Innovation Competition (iWEM)},
month = {11},
pages = {1-3},
publisher = {IEEE},
title = {Excitation Phase Control of Parallel-Fed Waveguide Slot Array Antenna Using Printed Circuit Board Single-Layer Structure Transmit Array},
url = {https://ieeexplore.ieee.org/document/9790685/},
year = {2021},
}
@inproceedings{Emara2021,
abstract = {A single-layered quarter-wave plate (QWP) is proposed and demonstrated for linear-to-circular polarization (LP-to-CP) conversion in the near-field of a slot array antenna. The QWP is based on a square unit cell with five elliptically shaped air holes - four on the edges and one in the center. The central ellipse is rotated by 45° which decomposes the incoming linear polarization into two orthogonally polarized components with 90° phase difference. The LP-to-CP conversion is demonstrated by simulating the proposed QWP in the near-field of an LP slot array antenna with a 3 dB axial ratio and -10 dB matching bandwidths of 5.1% and 8.9%, respectively, around 60 GHz.},
author = {Mohamed K. Emara and Takashi Tomura and Jiro Hirokawa and Shulabh Gupta},
doi = {10.1109/APS/URSI47566.2021.9704280},
isbn = {978-1-7281-4670-6},
journal = {2021 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting (APS/URSI)},
keywords = {linear-to-circular polarization conversion,metasurfaces,near-field engineering,quarter-wave plate},
month = {12},
pages = {195-196},
publisher = {IEEE},
title = {Millimeter-Wave Quarter-Wave Plate for Diffusion Bonded Slot Array Antennas},
url = {https://ieeexplore.ieee.org/document/9704280/},
year = {2021},
}
@inproceedings{Rahmeier2021,
abstract = {The problem of extracting the leakage factor and dispersion relation of a general periodic Leaky-Wave Antenna (LWA) is addressed using a complex eigenmode approach. The mapping between complex eigenmodes (ß, Ω) and the driven-mode dispersion relation (γ, ω0) is used to extract the leakage factor of a radiating periodic LWA, and demonstrated using a slot array antenna as an example. The dispersion relation extracted from the unit cell mapping process shows an excellent agreement with an otherwise computationally intensive full-wave driven-mode simulation.},
author = {Joao G. Nizer Rahmeier and Mohamed K. Emara and Shulabh Gupta},
doi = {10.1109/APS/URSI47566.2021.9703931},
isbn = {978-1-7281-4670-6},
journal = {2021 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting (APS/URSI)},
month = {12},
pages = {1367-1368},
publisher = {IEEE},
title = {Dispersion Relation Extraction of Periodic Leaky-Wave Antennas using Complex Eigenmodes},
url = {https://ieeexplore.ieee.org/document/9703931/},
year = {2021},
}
@inproceedings{Tiukuvaara2021,
abstract = {Using an Integral Equation (IE) based electromagnetic field solver that is capable of modeling metasurfaces (MSs) using the generalized sheet transition conditions (GSTCs), we study the accuracy of surface susceptibilities for modeling curvilinear surfaces. The surface susceptibilities are first extracted for a simple practical unit cell with a metal loop exhibiting a strong normal magnetic polarization. Subsequently, a uniform MS in the shape of a semi-circle is modeled using the GSTCs, and compared to full-wave simulations. We demonstrate that the GSTCs can successfully model curved surfaces, with minor discrepancies occurring when the curvature becomes extreme.},
author = {Ville Tiukuvaara and Tom J. Smy and Shulabh Gupta},
doi = {10.1109/APS/URSI47566.2021.9703709},
isbn = {978-1-7281-4670-6},
journal = {2021 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting (APS/URSI)},
month = {12},
pages = {1515-1516},
publisher = {IEEE},
title = {Investigation into Curvilinear Metasurfaces using IE-GSTCs with Normal Surface Polarizabilities},
url = {https://ieeexplore.ieee.org/document/9703709/},
year = {2021},
}
@inproceedings{Rahmeier2021,
abstract = {A systematic method to represent and analyze a practical nonlinear metasurface exhibiting temporal dispersion, using an equivalent zero thickness sheet model is proposed. The method is based on Generalized Sheet Transition Conditions (GSTCs), where the metasurface is described in terms of linear and nonlinear surface polarization densities modeled using a nonlinear Lorentz oscillator. The equivalent Lorentz parameters are extracted from unit cell simulations, and using numerical examples, it is shown that they can successfully replicate the dispersion and intensity-dependent nonlinear response of the finite-thickness metasurface.},
author = {Joao G. Nizer Rahmeier and Tom Smy and Jeremy Upham and Robert W. Boyd and Shulabh Gupta},
doi = {10.1109/APS/URSI47566.2021.9704345},
isbn = {978-1-7281-4670-6},
journal = {2021 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting (APS/URSI)},
month = {12},
pages = {197-198},
publisher = {IEEE},
title = {Zero Thickness Sheet Model of Dispersive & Nonlinear Metasurfaces},
url = {https://ieeexplore.ieee.org/document/9704345/},
year = {2021},
}
@article{Emara2021,
abstract = {Novel Fabry-Pérot resonator-based compound Huygens' structure with two all-dielectric metasurface layers is proposed and experimentally demonstrated. This design consists of two dielectric layers with about a quarter-wavelength separation at the center frequency. Each layer is a 2-D lattice of dielectric resonators. To realize the structure mechanically, each dielectric resonator is connected with its neighboring resonators using four interconnections or 'two bridges.' The two bridges allow for a mechanically strong design with low fabrication tolerances. The two layers are used to cancel the reflections from the bridges, and hence achieve low backscattering in a wide bandwidth. Full-wave simulations are used to realize various beam transformations in the millimeter-wave (mm-wave) band, such as refracted and difference-pattern (DP) beams. The proposed structure is also successfully demonstrated using experiments for the uniform and DP beams at the mm-waves.},
author = {Mohamed K. Emara and Takashi Tomura and Jiro Hirokawa and Shulabh Gupta},
doi = {10.1109/TAP.2020.3005233},
issn = {0018-926X},
issue = {1},
journal = {IEEE Transactions on Antennas and Propagation},
keywords = {Beamforming,Fabry-Pérot resonator,Huygens' structure,dielectric structure,difference-pattern (DP),millimeter-wave (mm-wave),reflection-canceling,refraction,slot-Array antenna},
month = {1},
pages = {273-285},
title = {All-Dielectric Fabry–Pérot-Based Compound Huygens’ Structure for Millimeter-Wave Beamforming},
volume = {69},
url = {https://ieeexplore.ieee.org/document/9132635/},
year = {2021},
}
@article{Emara2020,
abstract = {An all-dielectric Fabry-Pérot compound Huygens' structure is proposed for beam-forming at the millimeter-wave (mm-wave) band for circularly polarized (CP) waves. The proposed structure is based on a symmetric unit cell in the plane of the structure, which allows for CP wave transmission, and is demonstrated in the near field of a 60 GHz right-hand CP slot array antenna. Full-wave demonstration of a uniform structure shows a negligible effect on the reflection and radiation of the antenna from 59 to 62 GHz. Full-wave simulations were further used to demonstrate a phase-gradient structure for beam-steering from 59 to 61 GHz. Finally, a difference-pattern structure was fabricated and experimentally demonstrated for operation from 61 to 62 GHz, exhibiting low reflection and good axial ratio (AR) performance across the bandwidth.},
author = {Mohamed K. Emara and Takashi Tomura and Jiro Hirokawa and Shulabh Gupta},
doi = {10.1109/LAWP.2020.3018076},
issn = {1536-1225},
issue = {10},
journal = {IEEE Antennas and Wireless Propagation Letters},
keywords = {All-dielectric metasurface,Huygens' transmit-array,beam-forming,circular polarization,difference-pattern,millimeter-wave (mm-wave),refraction},
month = {10},
pages = {1784-1788},
title = {Fabry–Pérot-Based Compound All-Dielectric Huygens’ Structure for Circularly Polarized Millimeter-Wave Beamforming},
volume = {19},
url = {https://ieeexplore.ieee.org/document/9171434/},
year = {2020},
}
@inproceedings{Smy2020,
abstract = {A methodology to synthesize metasurface holograms to produce desired electromagnetic illusions is presented and demonstrated using a numerical example. The metasurface is described in terms of surface susceptibilities, which are synthesized using Generalized Sheet Transition Conditions (GSTCs), and the scattered-field computation using Boundary Element Method (BEM). The impact of spatial phase discretization on the reconstruction of the fields is further shown using a numerical example of plane-wave scattering from a PEC rectangular object.},
author = {Tom J. Smy and Shulabh Gupta},
doi = {10.1109/IEEECONF35879.2020.9329861},
isbn = {978-1-7281-6670-4},
journal = {2020 IEEE International Symposium on Antennas and Propagation and North American Radio Science Meeting},
month = {7},
pages = {921-922},
publisher = {IEEE},
title = {Electromagnetic Illusions created using Metasurface Holograms with Finite-Sized Unit Cells},
url = {https://ieeexplore.ieee.org/document/9329861/},
year = {2020},
}
@inproceedings{Emara2020,
abstract = {Accuracy and precision of positioning, navigation, and timing using the Global Navigation Satellite System (GNSS) is important for current and future applications such as autonomous vehicles and Internet of Things. A major threat to the accuracy and precision of GNSS is multipath interference from reflections around the antenna. To combat this issue, reference station antennas use corrugated ground planes to suppress multipath signals. In this paper, a comparative study of performance, size, and weight of six corrugated ground plane solutions is presented.},
author = {Mohamed K. Emara and Shulabh Gupta},
doi = {10.1109/IEEECONF35879.2020.9329810},
isbn = {978-1-7281-6670-4},
journal = {2020 IEEE International Symposium on Antennas and Propagation and North American Radio Science Meeting},
keywords = {choke ring,corrugated structures,global navigation satellite system,multipath mitigation,surface wave suppression},
month = {7},
pages = {1727-1728},
publisher = {IEEE},
title = {A Comparative Study of Corrugated Ground Planes for GNSS Multipath Mitigation},
url = {https://ieeexplore.ieee.org/document/9329810/},
year = {2020},
}
@inproceedings{Emara2020,
abstract = {The conditions for broadside radiation with no open stop-band are derived using a field based metasurface model of a general leaky-wave antenna (LWA). Using the Generalized Sheet Transition Conditions (GSTCs), the unique set of surface susceptibilities describing the metasurface to enable broadside radiation is obtained and it is found that the LWA must exhibit orthogonal electric and magnetic field dipole moments forming a Huygens' source configuration. The susceptibilities must further be lossy and satisfy a unique amplitude and phase relationship between the two.},
author = {Mohamed K. Emara and Shulabh Gupta},
doi = {10.1109/IEEECONF35879.2020.9329719},
isbn = {978-1-7281-6670-4},
journal = {2020 IEEE International Symposium on Antennas and Propagation and North American Radio Science Meeting},
month = {7},
pages = {97-98},
publisher = {IEEE},
title = {Broadside Radiation Problem in Leaky Wave Antennas: A Metasurface Perspective},
url = {https://ieeexplore.ieee.org/document/9329719/},
year = {2020},
}
@inproceedings{King2020,
abstract = {This study examines the conductive ink minimization of 5G engineered electromagnetic surfaces (EESs) made from meshed conductors. The paper demonstrates that the uniform meshed EES has (considerably) less conductor coverage than a solid metal area version without significantly compromising the performance, with the added benefit of increased optical transparency. Simulated results are presented in support of the novel EES topologies.},
author = {Daniel King and Khelifa Hettak and Reza Chaharmir and Jonathan Ethier and Shulabh Gupta},
doi = {10.1109/IEEECONF35879.2020.9329687},
isbn = {978-1-7281-6670-4},
journal = {2020 IEEE International Symposium on Antennas and Propagation and North American Radio Science Meeting},
keywords = {5G,Engineered electromagnetic surface,frequency selective surface,ink minimization,metasurafce,printed electronic},
month = {7},
pages = {1865-1866},
publisher = {IEEE},
title = {Ink Minimized Meshed Frequency Selective Surfaces with Increased Optical Transparency for 5G},
url = {https://ieeexplore.ieee.org/document/9329687/},
year = {2020},
}
@inproceedings{Rahmeier2020,
abstract = {Nanomagnetic circuits are characterized by propagating information via dipolar coupling. When a nanomagnetic wire is inserted to extract the result of a majority gate it fails to propagate the information in some cases. This happens due to undesired diagonal couplings between magnets of the majority gate and those that compose the wire. In this paper we analyze the dipolar coupling tensor to identify particles involved in such error cases. After that, we minimize undesired interactions and maximize desired ones by inserting geometry alterations in some nanomagnets of interest. All circuits are simulated using a Runge-Kutta numerical implementation of the Landau-Lifshitz-Gilbert equation. The proposed optimized circuit works for all input combinations.},
author = {Joao G. N. Rahmeier and Shulabh Gupta and Luiz G. C. Melo and Omar Vilela Neto},
doi = {10.1109/IEEECONF35879.2020.9329638},
isbn = {978-1-7281-6670-4},
journal = {2020 IEEE International Symposium on Antennas and Propagation and North American Radio Science Meeting},
month = {7},
pages = {799-800},
publisher = {IEEE},
title = {Geometry-based Optimization of an in-Plane Nanomagnetic Majority Circuit},
url = {https://ieeexplore.ieee.org/document/9329638/},
year = {2020},
}
@inproceedings{King2020,
abstract = {Two methods for synthesizing the phase profile of a reflective metasurface are presented based on Woodward-Lawson (WL) method and amplitude-to-phase mapping techniques. Using a simple square loop resonator based unit cell at 60 GHz, WL method is full-wave verified to approximate the desired far-field beam patterns. To improve the synthesis performance, a direct complex amplitude-to-phase mapping, is further presented which closely approximates any arbitrary pattern characteristics using phase-only modulated metasurfaces.},
author = {Daniel King and Khelifa Hettak and Reza Chaharmir and Jonathan Ethier and Shulabh Gupta},
doi = {10.1109/IEEECONF35879.2020.9330451},
isbn = {978-1-7281-6670-4},
journal = {2020 IEEE International Symposium on Antennas and Propagation and North American Radio Science Meeting},
month = {7},
pages = {917-918},
publisher = {IEEE},
title = {Phase-Only Synthesis Methods for General Beam-forming Reflective Metasurfaces},
url = {https://ieeexplore.ieee.org/document/9330451/},
year = {2020},
}
@article{Emara2020,
abstract = {A novel millimeter-wave (mm-wave) amplitude-only direction finding (DF) antenna front-end is proposed and experimentally demonstrated based on multiport leaky-wave antennas (LWAs). The multiport LWA is realized using an array of N linearly polarized slot antennas. Each slot antenna is engineered to produce a beam pointing along a specific direction, exploiting the beam scanning law of LWAs. Realizing progressively shifted beams angularly in space by controlling the slot geometry of each antenna, the multiport LWA becomes sensitive to a large finite angular sector. Using this architecture, a unique mapping between the angle of arrival (AoA) and the port locations is achieved. Using detailed full-wave simulations, the DF operation of the slot-based LWA is successfully demonstrated for several examples involving single and multiple signals illuminating the antenna. It is demonstrated that the AoA can be determined by measuring the received power at each of the ports and the known radiation patterns of the LWAs. The DF antenna front-end is demonstrated experimentally at 60 GHz using a ten-port slot array antenna fabricated using substrate integrated waveguide (SIW) technology and tested in various incoming signal scenarios.},
author = {Mohamed K. Emara and Daniel J. King and Hoang V. Nguyen and Samer Abielmona and Shulabh Gupta},
doi = {10.1109/TAP.2020.2979284},
issn = {0018-926X},
issue = {7},
journal = {IEEE Transactions on Antennas and Propagation},
keywords = {5G systems,amplitude-only direction finding (DF),angle of arrival (AoA),millimeter-wave (mm-wave),slot array antenna},
month = {7},
pages = {5365-5374},
title = {Millimeter-Wave Slot Array Antenna Front-End for Amplitude-Only Direction Finding},
volume = {68},
url = {https://ieeexplore.ieee.org/document/9036078/},
year = {2020},
}
@article{Botros2020,
abstract = {Direct thermal testing of aperiodic all-dielectric structures is presented, and its high-Q and emissivity properties are experimentally demonstrated for carbon dioxide (CO 2) gas sensing applications. Using a 7-layer dielectric stack consisting of alternating layers of silicon (Si) and silicon dioxide (SiO 2), backed by a metallic ground plane, an emissivity of 0.7 and a Q-factor of 113 are achieved at 70 ° C. Although this structure was already proposed in the literature, this is the first time direct thermal testing is reported, thereby showing narrowband emission properties of such structures when heated above room temperatures. An all-dielectric stack is thus found to be a simple, deposition-based structure that does not require any lateral mask preparation as frequency selectivity is achieved using an aperiodic arrangement of alternating dielectrics with contrasting permittivity. Superior performance over the periodically stacked structure is also demonstrated using numerical examples.},
author = {Joseph Botros and Muhammad O. Ali and R. Niall Tait and Rony E. Amaya and Shulabh Gupta},
doi = {10.1063/1.5140010},
issn = {0021-8979},
issue = {11},
journal = {Journal of Applied Physics},
month = {3},
pages = {114502},
title = {Direct thermal emission testing of aperiodic dielectric stack for narrowband thermal emission at mid-IR},
volume = {127},
url = {http://aip.scitation.org/doi/10.1063/1.5140010},
year = {2020},
}
@inproceedings{Emara2020,
abstract = {A novel all-dielectric Huygens' metasurface pair capable of circularly-polarized beam-forming is proposed. The proposed structure consists of two layers of dielectric resonators separated by approximately one quarter-wavelength at the design frequency. Each dielectric resonator is symmetrical to allow for the transmission of circularly-polarized waves. In order to physically design the structure, each resonator is connected to neighboring resonators using four symmetrical bridges. The second dielectric layer is added to cancel reflections caused by the bridges, allowing for the achievement of perfect matching. Fullwave simulations are used to demonstrate the full phase range achieved by varying unit cell dimensions. The operation of the proposed metasurface is further demonstrated by obtaining refracted and difference-pattern beams from a circularly-polarized slot array antenna.},
author = {Mohamed K. Emara and Takashi Tomura and Jiro Hirokawa and Shulabh Gupta},
doi = {10.23919/EuCAP48036.2020.9135253},
isbn = {978-88-31299-00-8},
journal = {2020 14th European Conference on Antennas and Propagation (EuCAP)},
keywords = {Huygens,Huygens' metasurface,beam-forming,circular polarization,difference-pattern,directive antennas,metasurface,millimeter-wave antennas,phase gradient metasurface.,refraction,slot arrays},
month = {3},
pages = {1-4},
publisher = {IEEE},
title = {All-Dielectric Huygens’ Metasurface Pair for mm-Wave Circularly-Polarized Beam-Forming},
url = {https://ieeexplore.ieee.org/document/9135253/},
year = {2020},
}
@inproceedings{Rahmeier2020,
abstract = {This paper presents a rigorous mathematical map- ping between the complex eigenmodes and the complex propagation constant for a homogeneous lossy waveguide structure. We validate the results for a rectangular waveguide, comparing the analytical mapping with the results from a FEM-EM solver. It has been found that a precise mapping between Ω(β) and γ(Ω) exists, which enables predicting the driven mode solution from the eigenmode analysis. While valid for a simple canonical case of a dispersive waveguide, such mapping establishes the underlying principles of how the complex eigenmodes are formulated inside typical commercial simulators.},
author = {Joao G. Nizer Rahmeier and Ville Tiukuvaara and Shulabh Gupta},
doi = {10.23919/EuCAP48036.2020.9135874},
isbn = {978-88-31299-00-8},
journal = {2020 14th European Conference on Antennas and Propagation (EuCAP)},
month = {3},
pages = {1-4},
publisher = {IEEE},
title = {Mapping Between Complex Eigenmodes and Complex Propagation Constant for Uniform Rectangular Metallic Waveguides},
url = {https://ieeexplore.ieee.org/document/9135874/},
year = {2020},
}
@inproceedings{Botros2020,
abstract = {A simple stacked dielectric structure is presented to achieve a broadband filtering response at millimeter-wave (mm-wave) frequencies. The structure consists of alternative slabs of different dielectric materials (non-periodic designs possible) to exhibit a bandpass response. The structure is designed using a transmission line model and confirmed with full-wave simulations. Compared to standard printed circuit board (PCB) fabrication, stacked dielectric structures are expected to exhibit better loss performance, due to absence of metallic patterns, and be easier to fabricate at mm-waves because of the absence of constraints from PCB line-width/gap dimension tolerances. An example structure was designed, fabricated, and measured with a center frequency 57 GHz consisting of three dielectric slabs and two air gaps. ANSYS FEM-HFSS simulations of this structure show well-matched bandpass performance, insertion loss of less than 1 dB, and a 3-dB bandwidth of 4.5 GHz. Measurement of the fabricated structure shows excellent performance and correlation with simulation.},
author = {Joseph Botros and Mohamed K. Emara and Rony E. Amaya and Shulabh Gupta},
doi = {10.23919/EuCAP48036.2020.9135939},
isbn = {978-88-31299-00-8},
journal = {2020 14th European Conference on Antennas and Propagation (EuCAP)},
keywords = {bandpass filters,dielectric devices,frequency selective surfaces,millimeter wave propagation},
month = {3},
pages = {1-4},
publisher = {IEEE},
title = {Millimeter-wave Bandpass Frequency Selective Structure Using Stacked Dielectric Slabs},
url = {https://ieeexplore.ieee.org/document/9135939/},
year = {2020},
}
@inproceedings{Tiukuvaara2020,
abstract = {Space-modulated diffraction gratings are modelled and analyzed using a zero thickness metasurface grating approach, and demonstrated using numerical examples. The constitutive parameters of the grating are described using surface susceptibilities of the Lorentzian form, where their resonant frequencies are sinusoidally modulated. They are then solved self-consistently with the Generalized Sheet Transition Conditions (GSTCs) to determine the scattered fields from the metasurface for specified plane-wave incident fields, for various cases of modulation periodicities and depths.},
author = {Ville Tiukuvaara and Tom J. Smy and Shulabh Gupta},
doi = {10.23919/EuCAP48036.2020.9135486},
isbn = {978-88-31299-00-8},
journal = {2020 14th European Conference on Antennas and Propagation (EuCAP)},
keywords = {Diffraction Gratings,Floquet Analysis,Generalized Sheet Transition Conditions (GSTCs),Lorentz Dispersion,Space-Time Modulated Metasurfaces},
month = {3},
pages = {1-4},
publisher = {IEEE},
title = {Metasurface Modeling of Periodic Diffraction Gratings based on Generalized Sheet Transition Conditions (GSTCs)},
url = {https://ieeexplore.ieee.org/document/9135486/},
year = {2020},
}
@inproceedings{Emara2020,
abstract = {A novel analog and real-time spectral decomposition system for signal processing at millimeter-wave (mmwave) frequencies is proposed and demonstrated using full-wave simulations. The system is based on a multi-port leaky-wave antennas (LWAs) structure formed using an array of N 1-D LWAs with 2 N ports. When this structure receives a broadband time-domain signal from a single direction, the signal's various spectral components are separated in real-time. They subsequently appear at the various ports of the LWAs following their respective beam-scanning laws. The proposed concept is demonstrated using frequency and time-domain full-wave simulations of two slot array antennas to decompose a transient pulse into four frequencies. The frequency outputs are then correlated back to the beam-scanning laws of the antennas.},
author = {Mohamed K. Emara and Shulabh Gupta},
doi = {10.23919/EuCAP48036.2020.9135309},
isbn = {978-88-31299-00-8},
journal = {2020 14th European Conference on Antennas and Propagation (EuCAP)},
keywords = {analog signal processing,leaky-wave antennas,millimeter-waves,real-time signal processing,spectral decomposition},
month = {3},
pages = {1-4},
publisher = {IEEE},
title = {Multi-Port Leaky-Wave Antennas as Real-Time Analog Spectral Decomposers},
url = {https://ieeexplore.ieee.org/document/9135309/},
year = {2020},
}
@inproceedings{Ashoor2020,
abstract = {A novel configuration of a metasurface unit cell is proposed to independently control its reflection phase and magnitude at the specified frequency and is demonstrated using an equivalent circuit model. The unit cell of the proposed metasurface structure consists of two resonators with integrated resistive and capacitive loads in each resonator, which are respectively responsible for dynamically controlling the reflection magnitude and phase. An equivalent circuit model of such confirmation is developed to study the reflection response of the metasurface as a function of various lumped-element controls. It is shown that an arbitrary combination reflection amplitude and phase can be achieved by appropriate combination of these lumped elements. Using commonly available tunable resistive and capacitive components, a real-time tunable metasurface is envisioned where the reflection amplitude and phase of the metasurface can be engineered with complete flexibility.},
author = {Ahmed Z. Ashoor and Shulabh Gupta},
doi = {10.23919/EuCAP48036.2020.9135493},
isbn = {978-88-31299-00-8},
journal = {2020 14th European Conference on Antennas and Propagation (EuCAP)},
keywords = {Equivalent circuit,metasurfaces,reflection magnitude,reflection phase,tunable metasurface},
month = {3},
pages = {1-4},
publisher = {IEEE},
title = {Towards Real-time Independent Control of Reflection Magnitude and Phase in Electromagnetic Metasurfaces},
url = {https://ieeexplore.ieee.org/document/9135493/},
year = {2020},
}
@inproceedings{Smy2020,
abstract = {This paper presents a general formulation for determining the scattered Electromagnetic fields present for a multi-surface configuration of curvilinear interfaces comprised of metasurfaces, dielectrics and perfect conductors. The method uses a Boundary Element Method (BEM) formulation of the frequency domain version of Maxwell's equations, where the general metasurface boundaries are represented in terms of surface susceptibilities which are then integrated within the BEM using the Generalized Sheet Transition Conditions (GSTCs). These curvilinear surfaces are next described by parametric equations allowing for an elegant formulation for geometrically complex systems. The proposed method is then demonstrated using a numerical example.},
author = {Tom. J. Smy and Jacob Connor and Scott A. Stewart and Shulabh Gupta},
doi = {10.23919/EuCAP48036.2020.9135851},
isbn = {978-88-31299-00-8},
journal = {2020 14th European Conference on Antennas and Propagation (EuCAP)},
month = {3},
pages = {1-4},
publisher = {IEEE},
title = {General Formulation of the Boundary Element Method (BEM) for Curvilinear Metasurfaces in the Presence of Multiple Scattering Objects},
url = {https://ieeexplore.ieee.org/document/9135851/},
year = {2020},
}
@article{Ali2020,
abstract = {A conductor-backed dielectric metasurface thermal emitter at mid-IR frequencies with narrowband emissivity is experimentally demonstrated. The metasurface emitter consists of a high permittivity silicon resonator on top of a ground plane, whose resonant mechanism is explained using image theory. The resonator, placed close to a copper ground plane, is designed to produce a magnetic resonance, resulting in a low-profile device with a single emission peak in its subwavelength frequency range. The thermal emitter is next fabricated using common CMOS processes. Frequency dependent optical constants of plasma-enhanced chemical vapor deposited films of Si, SiO 2, and evaporated Cu are also reported in the mid-IR range. Narrowband thermal emission is successfully obtained at around 7.22 μ m (41.5 THz), which corresponds to the absorption band of SO 2. The Q-factor of about 37 is achieved with a peak emissivity of 0.65, which is significantly higher compared to the reported Q-factors of state-of-the-art plasmonic resonators.},
author = {Muhammad O. Ali and R. Niall Tait and Shulabh Gupta},
doi = {10.1063/1.5125652},
issn = {0021-8979},
issue = {3},
journal = {Journal of Applied Physics},
month = {1},
pages = {033105},
title = {Conductor-backed dielectric metasurface thermal emitters for mid-infrared spectroscopy},
volume = {127},
url = {http://aip.scitation.org/doi/10.1063/1.5125652},
year = {2020},
}
@article{Smy2020,
abstract = {A systematic numerical framework based on Integral Equations and Generalized Sheet Transition Conditions (IE-GSTCs) is presented in 2D to synthesize closed metasurface holograms and skins for creating electromagnetic illusions of specified objects and as a special case, to camouflaging them against their backgrounds. The versatile hologram surface is modeled using a zero-thickness sheet model of a generalized metasurface expressed in terms of its surface susceptibilities, which is further integrated into the GSTCs and the IE current-field propagation operators. To estimate the effectiveness of the illusions, the notion of a scene constructed by an observer is developed from first principles and a simple mathematical model, referred to as a Structured Field Observation (SFO), based on spatial Fourier transform is proposed. Using numerical examples, it is shown that to recreate the reference desired fields everywhere in space using a closed metasurface hologram/skin, an internal illumination must be applied inside the hologram, in addition to the applied external illumination fields. Finally, several numerical examples are presented for simple, angle-dependent and dynamic illusions. Finally, a dynamic camouflaged region of space, which can freely move inside a given complex scene without being detected by the observer is demonstrated.},
author = {Tom J. Smy and Shulabh Gupta},
doi = {10.1109/ACCESS.2020.3045753},
issn = {2169-3536},
journal = {IEEE Access},
keywords = {Boundary Element Method (BEM),Effective Surface Susceptibilities,Electromagnetic Camouflage,Electromagnetic Illusions,Electromagnetic Metasurfaces,Field Scattering,Generalized Sheet Transition Conditions (GSTCs),Holograms,Method of Moments (MoM)},
pages = {226866-226886},
title = {Surface Susceptibility Synthesis of Metasurface Skins/Holograms for Electromagnetic Camouflage/Illusions},
volume = {8},
url = {https://ieeexplore.ieee.org/document/9298768/},
year = {2020},
}
@article{Emara2020,
abstract = {An all-dielectric Huygens' transmit-array is proposed and experimentally demonstrated in the 120-GHz-band. The proposed transmit-array is fabricated using a high-precision laser-drilling process providing high fabrication precision and accuracy. A non-uniform Huygens' surface is next placed on top of a planar high gain slot-array antenna for far-field beamforming. Full-wave simulations are first used to demonstrate the beamforming capability by generating difference-pattern beams as an example. A uniform transmit-array was then fabricated and characterized to investigate the effect of the transmit-array on the antenna performance, along with showing very low fabrication tolerances and minimal dimensional variation due to the laser drilling process. Next, a phase-gradient transmit-array for beam-tilting is experimentally demonstrated as a practical example of beamforming. The proposed all-dielectric structure is the first Huygens' structure to be demonstrated at these frequency bands, and represents an attractive alternative to conventional metallic Huygens' metasurfaces based on standard printed circuit board (PCB) solutions.},
author = {Mohamed K. Emara and Sonya K. Stuhec-Leonard and Takashi Tomura and Jiro Hirokawa and Shulabh Gupta},
doi = {10.1109/ACCESS.2020.3018297},
issn = {2169-3536},
journal = {IEEE Access},
keywords = {6G networks,Huygens' transmit-array,all-dielectric metasurface,beamforming,difference-pattern,laser-drilling,millimeter-wave (mm-wave),refraction,slot array antenna},
pages = {153815-153825},
title = {Laser-Drilled All-Dielectric Huygens’ Transmit-Arrays as 120 GHz Band Beamformers},
volume = {8},
url = {https://ieeexplore.ieee.org/document/9171827/},
year = {2020},
}
@article{Smy2020,
abstract = {A systematic approach is presented to exploit the rich field transformation capabilities of Electromagnetic (EM) metasurfaces for creating a variety of illusions using the concept of metasurface holograms. A system level approach to metasurface hologram synthesis is presented here, in which the hologram is co-designed with the desired object to be projected. A structured approach for the classification of the creation of EM illusions is proposed for better organization and tractability of the overall synthesis problem. The delineation is in terms of the initial incident (reference) illumination of the object to be recreated (front/back-lit), the position of illusion (posterior/anterior), and the illumination used to create the illusion (front/back). Therefore the classification is based on the specific relationship between the reference object to be recreated, the observer measuring the object, the orientation and placement of the reference and illumination field, and the desired placement of the metasurface hologram creating a virtual image. In the paper a general design procedure to synthesize metasurface holograms is presented based on Integral Equations (IE) and Generalized Sheet Transition Conditions (GSTCs), where the metasurface hologram is described as zero thickness sheet with tensorial surface susceptibility densities. Several selected configurations are chosen to illustrate various aspects of the hologram creation in 2D, along with a novel numerical technique to artificially reverse-propagate the scattered fields, required in the synthesis process. Finally, the impact of the metasurface size and the illumination field strength on the quality of the reconstructed scattered fields is also discussed.},
author = {Tom J. Smy and Scott A. Stewart and Shulabh Gupta},
doi = {10.1109/ACCESS.2020.2995358},
issn = {2169-3536},
journal = {IEEE Access},
keywords = {Electromagnetic metasurfaces,boundary element method (BEM),effective surface susceptibilities,electromagnetic illusions,field scattering,generalized sheet transition conditions (GSTCs),holograms,method of moments (MoM)},
pages = {93408-93425},
title = {Surface Susceptibility Synthesis of Metasurface Holograms for Creating Electromagnetic Illusions},
volume = {8},
url = {https://ieeexplore.ieee.org/document/9094677/},
year = {2020},
}
@article{Smy2020,
abstract = {A Finite-Difference Time-Domain (FDTD) simulation of broadband electromagnetic metasurfaces based on direct incorporation of Generalized Sheet Transition Conditions (GSTCs) into a conventional Yee-cell region has been proposed for arbitrary wave excitations. This is achieved by inserting a zero thickness metasurface inside bulk nodes of the Yee-cell region, giving rise to three distinct cell configurations - Symmetric Cell (SC), Asymmetric Cell (AC) and Tight Asymmetric Cell (TAC). In addition, the metasurface is modelled using electric and magnetic surface susceptibilities exhibiting a broadband Lorentzian response. As a result, the proposed model guarantees a physical and causal response from the metasurface. Several full-wave results are shown and compared with analytical Fourier propagation methods showing excellent results for both 1D and 2D field simulations. It is found that the TAC provides the fastest convergence among the three methods with minimum error.},
author = {Tom J. Smy and Scott A. Stewart and Joao G. N. Rahmeier and Shulabh Gupta},
doi = {10.1109/ACCESS.2020.2992656},
issn = {2169-3536},
journal = {IEEE Access},
keywords = {Finite-difference methods,Lorentz dispersion,Yee-cell,computational electromagnetics,electromagnetic diffraction,electromagnetic metamaterials,metasurfaces,time-domain analysis},
pages = {83027-83040},
title = {FDTD Simulation of Dispersive Metasurfaces With Lorentzian Surface Susceptibilities},
volume = {8},
url = {https://ieeexplore.ieee.org/document/9086476/},
year = {2020},
}
@inproceedings{Emara2019,
abstract = {A novel all-dielectric metasurface based on reflection cancelling Huygens' source pair is proposed for mm-wave beam-forming applications, and demonstrated using full-wave simulations. The metasurface is realized using an elliptical resonator connected with its neighbor using four dielectric bridges to provide mechanical stability. The quarter-wavelength spaced resonator pair is next used to achieve reflection cancelling, thereby matching the structure over a large bandwidth. By exploiting resonator ellipticities, transmission phase is engineered. Its application in beam-forming is next illustrated by realizing a monopulse pattern as an example.},
author = {Mohamed K. Emara and Takashi Tomura and Jiro Hirokawa and Shulabh Gupta},
doi = {10.1109/APUSNCURSINRSM.2019.8889322},
isbn = {978-1-7281-0692-2},
journal = {2019 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting},
month = {7},
pages = {433-434},
publisher = {IEEE},
title = {Reflection-Cancelling Dielectric Huygens’ Metasurface Pair for Wideband Millimeter-Wave Beam-Forming},
url = {https://ieeexplore.ieee.org/document/8889322/},
year = {2019},
}
@article{Stewart2019,
abstract = {This article presents a method to determine the scattered electromagnetic (EM) fields in the interconnected regions with common metasurface boundaries. This method uses a boundary element method (BEM) formulation of the frequency domain version of Maxwell's equations, which expresses the fields present in a region due to surface currents on the boundaries. Metasurface boundaries are represented in terms of surface susceptibilities which when integrated with the generalized sheet transition conditions (GSTCs) gave rise to an equivalent configuration in terms of electric and magnetic currents. These representations are then naturally incorporated into the BEM methodology. Four examples are presented for EM scattering of a Gaussian beam to illustrate the proposed method. In the first example, a metasurface is excited with a diverging Gaussian beam, and the scattered fields are validated using a semianalytical method. The second example is concerned with a nonuniform metasurface modeling a diffraction grating, whose results were confirmed with a conventional finite-difference frequency-domain (FDFD) method. To illustrate the flexibility of the method, the third example uses a metasurface that implements a polarization rotator. Finally, a fully absorbing metasurface is simulated and compared to the FDFD simulations to emphasize the advantages of BEM method.},
author = {Scott A. Stewart and Sanam Moslemi-Tabrizi and Tom J. Smy and Shulabh Gupta},
doi = {10.1109/TAP.2019.2935131},
issn = {0018-926X},
issue = {12},
journal = {IEEE Transactions on Antennas and Propagation},
keywords = {Boundary element method (BEM),electromagnetic metasurfaces,field scattering,generalized sheet transition conditions (GSTCs),method of moments (MOMs)},
month = {12},
pages = {7487-7495},
title = {Scattering Field Solutions of Metasurfaces Based on the Boundary Element Method for Interconnected Regions in 2-D},
volume = {67},
url = {https://ieeexplore.ieee.org/document/8805251/},
year = {2019},
}
@inproceedings{King2019,
abstract = {A simple procedure to extract the attenuation constant of a lossy traveling-wave structure using eigenmode simulations is presented. For lossy structures, the eigenmode analysis outputs complex eigenvalues which mathematically results in complex frequencies, ω. Using the proposed relations, these complex frequencies are mapped to the complex propagation constant γ and the corresponding attenuation constant α through the group velocity of the mode. Taking a standard rectangular waveguide as an example, complex eigenmodes are extracted through full-wave simulations, which are then used to correctly predict the the per-unit length attenuation constant under low-loss conditions.},
author = {Daniel J. King and Shulabh Gupta},
doi = {10.1109/APUSNCURSINRSM.2019.8888665},
isbn = {978-1-7281-0692-2},
journal = {2019 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting},
month = {7},
pages = {493-494},
publisher = {IEEE},
title = {Relation between Complex Propagation Constant and Complex Eigenmodes in Lossy Traveling-Wave Structures},
url = {https://ieeexplore.ieee.org/document/8888665/},
year = {2019},
}
@inproceedings{Emara2019,
abstract = {A low-cost light-weight 3D-printed copper coated choke ring is presented and experimentally demonstrated to have similar performance to a fully metallic choke ring. The conventional metallic choke ring is the standard ground plane used in global navigation satellite systems (GNSS) reference antennas to reject multipath signals. While the choke ring greatly enhances the performance of the antenna, it has the disadvantage of being heavy, bulky, and expensive. One method to reduce the weight and cost of the choke ring, while maintaining the same performance as the metallic structure, is to build the structure using a low-cost, light-weight dielectric material and coating the outside with an electric conductor. In this paper, a prototype of a novel 3D-printed choke ring made from polylactic acid (PLA) plastic and coated with copper tape is fabricated and tested. The novel choke ring is demonstrated to have the same performance as an otherwise heavy and expensive metallic choke ring.},
author = {Mohamed K. Emara and Khaled Madhoun and Rawan Madhoun and Shulabh Gupta},
doi = {10.1109/APUSNCURSINRSM.2019.8888998},
isbn = {978-1-7281-0692-2},
journal = {2019 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting},
month = {7},
pages = {721-722},
publisher = {IEEE},
title = {A Low-cost Light-weight 3D-printed Choke Ring for Multipath Mitigation for GNSS Antennas},
url = {https://ieeexplore.ieee.org/document/8888998/},
year = {2019},
}
@article{Emara2019,
abstract = {A phaser based on codirectional coupling is proposed and experimentally investigated to achieve a flat transmission magnitude while maintaining strong frequency-dependent group delay response. This is the first experimental demonstration of such devices for real-time radio analog signal processing applications, which are readily scalable to mm-wave frequencies. While shielding improved the transmission performance by mitigating the radiation, a gain element is introduced to achieve a perfectly flat transmission magnitude response. The proposed structure thus forms the fundamental building block of engineering more complex dispersion profiles without compromising transmission magnitude response.},
author = {Mohamed K. Emara and Shulabh Gupta},
doi = {10.1002/mop.31815},
issn = {0895-2477},
issue = {7},
journal = {Microwave and Optical Technology Letters},
keywords = {analog signal processing,codirectional couplers,dispersion engineering,group delay structures},
month = {7},
pages = {1778-1782},
title = {Experimental demonstration of active phasers based on codirectional coupling for real‐time analog signal processing},
volume = {61},
url = {https://onlinelibrary.wiley.com/doi/10.1002/mop.31815},
year = {2019},
}
@article{Stewart2019,
abstract = {An updated method for simulating the scattered fields from a dispersive Huygens' metasurface using the explicit finite-difference time-domain technique has been proposed and numerically demonstrated. The method uses a spatial-temporal averaging of the electric and magnetic fields, using virtual sources in a standard Yee cell grid. This creates a nonparaxial implementation of the generalized sheet transition conditions in the time domain and rigorously solves the scattered fields in reflection and transmission regions separately. The metasurfaces are solved for Lorentzian susceptibilities, and the proposed method is successfully demonstrated using two examples: a uniform metasurface with a strongly divergent beam and a space-modulated metasurface emulating a diffraction grating.},
author = {Scott Stewart and Sanam Moslemi-Tabrizi and Tom. J. Smy and Shulabh Gupta},
doi = {10.1109/LAWP.2019.2913510},
issn = {1536-1225},
issue = {6},
journal = {IEEE Antennas and Wireless Propagation Letters},
keywords = {Electromagnetic metasurfaces,Lorentz dispersion,finite-difference time domain (FDTD),generalized sheet transition conditions (GSTCs)},
month = {6},
pages = {1238-1242},
title = {Modified Explicit Finite-Difference Time-Domain Method for Nonparaxial Wave Scattering From Electromagnetic Metasurfaces},
volume = {18},
url = {https://ieeexplore.ieee.org/document/8700295/},
year = {2019},
}
@inproceedings{Emara2019,
abstract = {A simple multi-port antenna structure is proposed which can be used for direction finding (DF) and beam-forming applications in the receive and transmit modes, respectively. The proposed antenna offers unique functionalities in both receive and transmit modes. For DF applications in the receive mode, the beam-scanning laws of each antenna array is engineered to cover a given sector of space and the back-end of the system will feature a power sensing mechanism to monitor the power received at all ports. In the transmit mode, the proposed antenna can be used for beam-forming applications by engineering the individual port excitation and the antenna sub-arrays. The proposed antenna structure characteristics are demonstrated using full-wave simulations at 58-61 GHz based on circularly polarized slot arrays using substrate integrated waveguide (SIW) technology. Initial results show the antenna features high angle of arrival (AoA) resolution and a wide sector coverage, making it a good candidate for 5G wireless systems.},
author = {M.K. Emara and D.J. King and H. Nguyen and S. Abielmona and S. Gupta},
isbn = {9788890701887},
journal = {13th European Conference on Antennas and Propagation, EuCAP 2019},
keywords = {beam-forming millimeter-wave antennas,beam-scanning,circular polarization,direction finding,directive antennas,sector coverage,slot arrays},
title = {Multi-port Slot Array Antenna for Millimeter-wave Direction Finding and Beam-forming Applications},
year = {2019},
}
@inproceedings{Gupta2019,
abstract = {A novel mm-wave all-dielectric structure based on Huygens' metasurfaces is proposed to engineer the radiation fields of a 2D slot array antenna, and demonstrated using full-wave simulations. The proposed metasurface consists of elliptically-shaped resonators whose geometrical dimensions can be engineered to enable rich wave transformation capabilities. They are placed on top of the slot antenna array in its near-field zone and designed to transform the intrinsic uniform field distribution of the antenna to desired radiation patterns. A beam-tilting example has been presented to demonstrate the proposed principle.},
author = {S. Gupta and T. Tomura and S. Sakurai and D.J. King and J. Hirokawa},
isbn = {9788890701887},
journal = {13th European Conference on Antennas and Propagation, EuCAP 2019},
keywords = {Huygens' Sources,electromagnetic metasurfaces,millimeter-wave antennas,near-field operation,slot arrays},
title = {Millimeter-wave Huygens' Metasurfaces based on All-dielectric Resonators for Antenna Beam-forming},
year = {2019},
}
@inproceedings{King2019,
abstract = {A real-time, low-profile and shielded spectrum analyzer is proposed for operation at mm-wave frequencies based on Substrate Integrated Waveguide (SIW) technology. A novel unit cell is also proposed to enable an in-plane side-fire radiating Leaky Wave Antenna (LWA). The unit cell is inspired from a conventional T-junction and is equipped with an internal matching mechanism to suppress stop-band to achieve full-space radiation. The antenna characteristics and the system operation is confirmed using full-wave simulations. The proposed system is analog, broadband, real-time in nature, low-profile and compact in size; ideal for instrumentation applications.},
author = {D.J. King and M.K. Emara and S. Gupta},
isbn = {9788890701887},
journal = {13th European Conference on Antennas and Propagation, EuCAP 2019},
keywords = {beam-scanning,leaky-wave antenna,millimeter-wave antenna,near-field measurement,real time spectrum analyzer,side-fire antenna,stop-band suppression},
title = {Millimeter-wave Near-field Spectrum Analyzer Based on Integrated Side-fire Antennas},
year = {2019},
}
@inproceedings{Stewart2019,
abstract = {A semi-analytical method of calculating scattered fields from a uniform metasurface for an arbitrary monochromatic incident field is presented and confirmed with numerical simulations. A known incident field is first decomposed using a Fourier transform into a set of plane waves, and Generalized Sheet Transition Conditions (GTSCs) are next applied to each plane wave component to accurately determine the total scattering fields in the transmission and reflection regions. The proposed semi-analytical method represents a simple benchmarking tool to validate various numerical methods for analyzing metasurfaces.},
author = {S.A. Stewart and S. Moslemi-Tabrizi and T.J. Smy and S. Gupta},
isbn = {9788890701887},
journal = {13th European Conference on Antennas and Propagation, EuCAP 2019},
title = {Scattered Field Solutions of Uniform Metasurfaces using Plane-Wave Decomposition Method for Arbitrary Incident Waves},
year = {2019},
}
@article{Emara2019,
abstract = {A novel low-profile grooved-dielectric choke ring with dual-band surface impedance resonance is proposed and experimentally demonstrated. The proposed structure is designed by engineering the surface impedance of a dielectric-based choke ring to introduce two resonant frequencies around the global navigation satellite system (GNSS) bands of L2 (1227.60 MHz) and L1 (1575.42 MHz). This provides capacitive surface impedances around both bands simultaneously, which is required for efficient surface wave suppression for higher multipath rejection performance. To demonstrate the proposed principle of surface impedance engineering, an in-house choke ring prototype of the proposed design is tested with the widely used Dorne and Margolin antenna. A high multipath rejection in both GNSS bands is experimentally confirmed with comparable performances to an otherwise bulky, heavy, and expensive conventional metallic choke ring.},
author = {Mohamed K. Emara and Julien Hautcoeur and Gyles Panther and Jim S. Wight and Shulabh Gupta},
doi = {10.1109/TAP.2019.2891553},
issn = {0018-926X},
issue = {3},
journal = {IEEE Transactions on Antennas and Propagation},
keywords = {Artificial magnetic conductor (AMC),choke ring,corrugated structure,global navigation satellite system (GNSS),high impedance surface,multipath mitigation,surface wave suppression},
month = {3},
pages = {2008-2011},
title = {Surface Impedance Engineered Low-Profile Dual-Band Grooved-Dielectric Choke Ring for GNSS Applications},
volume = {67},
url = {https://ieeexplore.ieee.org/document/8606135/},
year = {2019},
}
@inproceedings{Emara2018,
abstract = {An active phaser based on co-directional couplers is proposed for achieving a flat magnitude transmission while preserving its strong dispersive delay response. The phasers are realized using Half-Mode Substrate Integrated Waveguide (HMSIW) structures, and are successfully demonstrated using full-wave simulations. Due to the non-TEM nature of the device, the proposed phasers are ideally suitable for mm-wave real-Time analog signal processing systems.},
author = {Mohamed K. Emara and Jim S. Wight and Shulabh Gupta},
doi = {10.1109/ANTEM.2018.8573017},
isbn = {978-1-5386-1338-2},
journal = {2018 18th International Symposium on Antenna Technology and Applied Electromagnetics (ANTEM)},
keywords = {active devices,analog signal processing (ASP),dispersion engineering,group delay engineering,phasers,substrate-integrated waveguides (SIW)},
month = {8},
pages = {1-3},
publisher = {IEEE},
title = {Active Phasers based on Co-directional Couplers for Millimeter-wave Analog Signal Processing},
volume = {2018-Augus},
url = {https://ieeexplore.ieee.org/document/8573017/},
year = {2018},
}
@inproceedings{Emara2018,
abstract = {A novel low-profile dual-band tunable artificial magnetic conductor (AMC) structure based on the choke ring is presented in this paper. The structure is tuned to the Global Navigation Satellite System (GNSS) frequencies of L2 (1227.60 MHz) and L1 (1575.42 MHz). Using full-wave simulations for the Dorne & Margolin (DM) antenna mounted on the AMC structure, it is demonstrated that the proposed dual-band structure provides good multipath performance at both L2 and L1. Compared to the conventional choke ring, the novel design provides a 52% reduction in height and a 26% reduction in diameter.},
author = {Mohamed K. Emara and Shulabh Gupta and Julien Hautcoeur and Gyles Panther and Jim S. Wight},
doi = {10.1109/ANTEM.2018.8573028},
isbn = {978-1-5386-1338-2},
journal = {2018 18th International Symposium on Antenna Technology and Applied Electromagnetics (ANTEM)},
keywords = {Global Navigation Satellite System (GNSS),artificial magnetic conductor (AMC),choke ring,dual-band,multipath},
month = {8},
pages = {1-4},
publisher = {IEEE},
title = {A Low-Profile Dual-Band Tunable AMC Structure for GNSS Antennas and Its Performance Trade-Offs},
volume = {2018-Augus},
url = {https://ieeexplore.ieee.org/document/8573028/},
year = {2018},
}
@inproceedings{Smy2018,
abstract = {A numerical comparison between the explicit and implicit finite difference time-domain (FDTD) methods is presented for simulating broadband and dispersive metasurfaces. It has been found that, while the implicit method is rigorous in computing the scattered fields in both reflection and transmission region of the metasurface, care must be taken using the explicit method, which is applicable under paraxial wave propagation conditions only.},
author = {Tom J. Smy and Scott A. Stewart and Shulabh Gupta},
doi = {10.23919/ROPACES.2018.8364138},
isbn = {978-0-9960-0787-0},
journal = {2018 International Applied Computational Electromagnetics Society Symposium (ACES)},
month = {3},
pages = {1-2},
publisher = {IEEE},
title = {Implicit and explicit FDTD methods for modelling EM metasurfaces},
url = {https://ieeexplore.ieee.org/document/8364138/},
year = {2018},
}
@inproceedings{Sheikh2018,
abstract = {A Huygens' unit cell configuration based on perforated dielectrics is proposed and demonstrated using full-wave simulations. The proposed unit cell consists of a high permittivity dielectric resonator surrounded by a honey-comb lattice. The Honey comb structure provides mechanical integrity to the unit cell, thereby enabling the unit cell scaling to mm-wave frequency bands. Two different designs are shown to demonstrate diversity of transmission characteristics achievable through the proposed cells.},
author = {Naquash A. Sheikh and Khaled Madhoun and Sonya Stuhec-Leonard and Shulabh Gupta},
doi = {10.23919/ROPACES.2018.8364137},
isbn = {978-0-9960-0787-0},
journal = {2018 International Applied Computational Electromagnetics Society Symposium (ACES)},
month = {3},
pages = {1-3},
publisher = {IEEE},
title = {Millimeter-wave electromagnetic metasurfaces based on perforated dielectrics},
url = {https://ieeexplore.ieee.org/document/8364137/},
year = {2018},
}
@inproceedings{Emara2018,
abstract = {An active microwave C-section phaser is proposed which provides a flat magnitude transmission in a wide frequency band along with a frequency-dependent group delay response considering practical dissipation losses. The key lies in integrating a constant gain amplifier inside a microwave C-section, which perfectly compensates the distributed conductor and dielectric losses of the coupler, while preserving the intrinsic dispersion of the C-section. The operation of the proposed device is confirmed using numerical analysis and full-wave simulations.},
author = {Mohamed K. Emara and Kimi Maheshwari and Jim S. Wight and Shulabh Gupta},
doi = {10.23919/ROPACES.2018.8364119},
isbn = {978-0-9960-0787-0},
journal = {2018 International Applied Computational Electromagnetics Society Symposium (ACES)},
month = {3},
pages = {1-2},
publisher = {IEEE},
title = {Amplitude-equalized microwave phasers},
url = {https://ieeexplore.ieee.org/document/8364119/},
year = {2018},
}
@article{Ali2018,
abstract = {A simple all-dielectric thermal emitter unit cell for narrowband gas-sensing application is proposed, providing large Q-factors compared to its plasmonic counterpart. It consists of a high-index dielectric-based elliptical puck on top of a back-reflector, providing narrowband thermal emission. Using full-wave simulations, it is demonstrated that the achievable Q-factors in this structure are orders of magnitude larger than what have been shown for plasmonic cells, thanks to their low-loss electrical characteristics. Furthermore, the thermal emission properties can be engineered by manipulating the geometry of the unit cell, whereby it is shown that these unit cells can provide polarized thermal emission simultaneously in two separate frequency bands, with identical Q-factor characteristics, depending on their ellipticity parameter.},
author = {Muhammad O. Ali and Niall Tait and Shulabh Gupta},
doi = {10.1364/JOSAA.35.000119},
issn = {1084-7529},
issue = {1},
journal = {Journal of the Optical Society of America A},
month = {1},
pages = {119},
title = {High-Q all-dielectric thermal emitters for mid-infrared gas-sensing applications},
volume = {35},
url = {https://opg.optica.org/abstract.cfm?URI=josaa-35-1-119},
year = {2018},
}
@inproceedings{Emara2018,
abstract = {A novel low-profile dual-band tunable artificial magnetic conductor (AMC) structure based on the choke ring is presented in this paper. The structure is tuned to the Global Navigation Satellite System (GNSS) frequencies of L2 (1227.60 MHz) and L1 (1575.42 MHz). Using full-wave simulations for the Dorne & Margolin (D&M) antenna mounted on the AMC structure, it is demonstrated that the proposed dual-band structure provides good multipath performance at both L2 and L1. Compared to the conventional choke ring, the novel design provides a 52% reduction in height and a 26% reduction in diameter.},
author = {M.K. Emara and S. Gupta and J.S. Wight and J. Hautcoeur and G. Panther},
doi = {10.1049/cp.2018.0901},
isbn = {978-1-78561-816-1},
issue = {CP741},
journal = {12th European Conference on Antennas and Propagation (EuCAP 2018)},
keywords = {Artificial magnetic conductor (AMC),Choke ring,Dual-band,Global Navigation Satellite System (GNSS),Multipath},
pages = {542 (4 pp.)-542 (4 pp.)},
publisher = {Institution of Engineering and Technology},
title = {A Low-Profile Dual-Band Tunable AMC Structure for GNSS Antennas and Its Performance Trade-Offs},
volume = {2018},
url = {https://digital-library.theiet.org/content/conferences/10.1049/cp.2018.0901},
year = {2018},
}
@article{Stewart2018,
abstract = {A finite-difference time-domain modeling of finite-size zero thickness space-time-modulated Huygens' metasurfaces based on generalized sheet transition conditions is proposed and numerically demonstrated. A typical all-dielectric Huygens' unit cell is taken as an example and its material permittivity is modulated in both space and time, to emulate a traveling-type spatio-temporal perturbation on the metasurface. By mapping the permittivity variation onto the parameters of the equivalent Lorentzian electric and magnetic susceptibility densities, χee and χmm, the problem is formulated into a set of second-order differential equations in time with nonconstant coefficients. The resulting field solutions are then conveniently solved using an explicit finite-difference technique and integrated with a Yee-cell-based propagation region to visualize the scattered fields taking into account the various diffractive effects from the metasurface of finite size. Several examples are shown for both linear and space-time varying metasurfaces which are excited with normally incident plane and Gaussian beams, showing detailed scattering field solutions. While the time-modulated metasurface leads to the generation of new collinearly propagating temporal harmonics, these harmonics are angularly separated in space, when an additional space modulation is introduced in the metasurface.},
author = {Scott A. Stewart and Tom. J. Smy and Shulabh Gupta},
doi = {10.1109/TAP.2017.2772045},
issn = {0018-926X},
issue = {1},
journal = {IEEE Transactions on Antennas and Propagation},
keywords = {Electromagnetic metamaterials,electromagnetic propagation,finite difference methods,time-domain analysis},
month = {1},
pages = {281-292},
title = {Finite-Difference Time-Domain Modeling of Space–Time-Modulated Metasurfaces},
volume = {66},
url = {http://ieeexplore.ieee.org/document/8103025/},
year = {2018},
}
@article{Zou2018,
abstract = {We model, demonstrate, and characterize dispersion code multiple access (DCMA), and hence, show the applicability of this purely analog and real-time multiple access scheme to high-speed wireless communications. We first mathematically describe DCMA and show the appropriateness of Chebyshev dispersion coding in this technology. We next provide an experimental proof-of-concept in a 2 × 2 DCMA system. Finally, we statistically characterize DCMA in terms of bandwidth, dispersive group delay swing, system dimension, and signal-to-noise ratio.},
author = {Lianfeng Zou and Shulabh Gupta and Christophe Caloz},
doi = {10.1109/TWC.2017.2765304},
issn = {1536-1276},
issue = {1},
journal = {IEEE Transactions on Wireless Communications},
keywords = {Dispersion code multiple access (DCMA),dispersion engineering,non-orthogonal multiple access (NOMA),phaser,radio real-time analog signal processing (RR-ASP)},
month = {1},
pages = {266-281},
title = {Real-Time Dispersion Code Multiple Access for High-Speed Wireless Communications},
volume = {17},
url = {http://ieeexplore.ieee.org/document/8086172/},
year = {2018},
}
@inproceedings{Gupta2017,
abstract = {An exact Floquet analysis is proposed to determine the steady-state response a uniform parametric Huygens' metasurface. Under periodic modulation of the resonant frequencies of the Lorentzian surface susceptibilities of the metasurface, the unknown scattered fields are expressed as Floquet series. Using the Floquet form of the fields in conjunction with the Generalized Sheet Transition Conditions (GSTCs), the amplitudes of the new harmonic components are then conveniently determined by solving the resulting set a linear fields equations.},
author = {Shulabh Gupta and Tom Smy},
doi = {10.1109/APUSNCURSINRSM.2017.8072898},
isbn = {978-1-5386-3284-0},
journal = {2017 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting},
month = {7},
pages = {1711-1712},
publisher = {IEEE},
title = {Floquet analysis of parametric huygens' metasurfaces},
volume = {2017-Janua},
url = {http://ieeexplore.ieee.org/document/8072898/},
year = {2017},
}
@inproceedings{Smy2017,
abstract = {A circuit based time-domain modelling of Huygens' metasurfaces is proposed and demonstrated using numerical examples. The model is based on Generalized Sheet Transition Conditions (GSTCs) and multi-Lorentz surface susceptibilities describing the metasurface. Using an LCR band-pass filter circuit, the surface susceptibilities are modelled for a general unmatched and lossy metasurface, allowing for both time and frequency domain computation of scattered fields capturing the corresponding dispersive effects.},
author = {Tom J. Smy and Scott A. Stewart and Shulabh Gupta},
doi = {10.1109/APUSNCURSINRSM.2017.8072897},
isbn = {978-1-5386-3284-0},
journal = {2017 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting},
month = {7},
pages = {1709-1710},
publisher = {IEEE},
title = {Time-domain circuit modelling of huygens' metasurfaces},
volume = {2017-Janua},
url = {http://ieeexplore.ieee.org/document/8072897/},
year = {2017},
}
@inproceedings{Stewart2017,
abstract = {A simple semi-Analytical technique to compute the steady-state field profile of new harmonic frequencies generated at the output of a space-Time modulated Huygens' metasurface is proposed and numerically demonstrated. For a given monochromatic excitation, the metasurface output fields are first computed using a finite-difference routine taking into account the Generalized Sheet Transition Conditions (GSTCs) and the Lorentzian surface susceptibilities. The field profiles in the surrounding region of the metasurface are then obtained by computing the temporal Fourier transforms of metasurface outputs and applying the analytical Fourier propagation to each of its harmonic components.},
author = {Scott A. Stewart and Tom Smy and Shulabh Gupta},
doi = {10.1109/APUSNCURSINRSM.2017.8072265},
isbn = {978-1-5386-3284-0},
journal = {2017 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting},
month = {7},
pages = {445-446},
publisher = {IEEE},
title = {Semi-Analytical finite-difference technique for steady-state field characterization of space-time modulated huygens' metasurfaces},
volume = {2017-Janua},
url = {http://ieeexplore.ieee.org/document/8072265/},
year = {2017},
}
@article{Taravati2017,
abstract = {We introduce a nonreciprocal nongyrotropic magnetless metasurface. In contrast to previous nonreciprocal structures, this metasurface does not require a biasing magnet, and is therefore lightweight and amenable to integrated circuit fabrication. Moreover, it does not induce Faraday rotation, and hence does not alter the polarization of waves, which is a desirable feature in many nonreciprocal devices. The metasurface is designed according to a Surface-Circuit-Surface architecture and leverages the inherent unidirectionality of transistors for breaking time reversal symmetry. Interesting features include transmission gain as well as broad operating bandwidth and angular sector operation. It is finally shown that the metasurface is bianisotropic in nature, with nonreciprocity due to the electric-magnetic coupling parameters, and structurally equivalent to a moving uniaxial metasurface.},
author = {Sajjad Taravati and Bakhtiar A. Khan and Shulabh Gupta and Karim Achouri and Christophe Caloz},
doi = {10.1109/TAP.2017.2702712},
issn = {0018-926X},
issue = {7},
journal = {IEEE Transactions on Antennas and Propagation},
keywords = {Gyrotropy,isolator,magnetless,metasurface,nonreciprocity},
month = {7},
pages = {3589-3597},
title = {Nonreciprocal Nongyrotropic Magnetless Metasurface},
volume = {65},
url = {http://ieeexplore.ieee.org/document/7922565/},
year = {2017},
}
@article{Smy2017,
abstract = {An explicit time-domain finite-difference technique for modeling zero-thickness Huygens' metasurfaces based on generalized sheet transition conditions (GSTCs) is proposed and demonstrated using full-wave simulations. The Huygens' metasurface is modeled using electric and magnetic surface susceptibilities, which are found to follow a double-Lorentz dispersion profile. To solve zero-thickness Huygens' metasurface problems for general broadband excitations, the double-Lorentz dispersion profile is combined with GSTCs, leading to a set of first-order differential fields equations in time domain. Identifying the exact equivalence between Huygens' metasurfaces and coupled RLC oscillator circuits, the field equations are then subsequently solved using standard circuit modeling techniques based on a finite-difference formulation. Several examples, including generalized refraction, are shown to illustrate the temporal evolution of scattered fields from the Huygens' metasurface under plane-wave normal incidence, in both harmonic steady-state and broadband regimes. In particular, due to its inherent time-domain formulation, a significant strength of the methodology is its ability to model time-varying metasurfaces, which is demonstrated with a simple example of a pumped metasurface leading to new frequency generation and wave amplification.},
author = {Tom J. Smy and Shulabh Gupta},
doi = {10.1109/TAP.2017.2681323},
issn = {0018-926X},
issue = {5},
journal = {IEEE Transactions on Antennas and Propagation},
keywords = {Electromagnetic (EM) metasurfaces,Lorentz dispersions,electromagnetic propagation,explicit finite difference,generalized sheet transition conditions (GSTCs)},
month = {5},
pages = {2566-2577},
title = {Finite-Difference Modeling of Broadband Huygens’ Metasurfaces Based on Generalized Sheet Transition Conditions},
volume = {65},
url = {http://ieeexplore.ieee.org/document/7875455/},
year = {2017},
}
@article{Zou2017,
abstract = {A picosecond pulse generator based on a pair of step recovery diodes (SRDs) is proposed. This generator leverages the transient response of the SRD p-n junction, and provides pulsewidth tunability via a resistor. We first explain the operation principle of the device, by decomposing the pulse generation into different phases, and then demonstrate an experimental prototype with two different pulse values.},
author = {Lianfeng Zou and Shulabh Gupta and Christophe Caloz},
doi = {10.1109/LMWC.2017.2690880},
issn = {1531-1309},
issue = {5},
journal = {IEEE Microwave and Wireless Components Letters},
keywords = {Real-time analog signal processing (R-ASP),Step recovery diode (SRD),Ultra-wideband pulse generator},
month = {5},
pages = {467-469},
title = {A Simple Picosecond Pulse Generator Based on a Pair of Step Recovery Diodes},
volume = {27},
url = {http://ieeexplore.ieee.org/document/7906510/},
year = {2017},
}
@article{Achouri2017,
abstract = {We introduce a practical dielectric metasurface design for microwave frequencies. The metasurface is made of an array of dielectric resonators held together by dielectric connections thus avoiding the need of a mechanical support in the form of a dielectric slab and the spurious multiple reflections that such a slab would generate. The proposed design can be used either for broadband metasurface applications or monochromatic wave transformations. The capabilities of the concept to manipulate the transmission phase and amplitude of the metasurface are supported by the numerical and experimental results. Finally, a half-wave plate and a quarter-wave plate have been realized with the proposed concept.},
author = {Karim Achouri and Ali Yahyaoui and Shulabh Gupta and Hatem Rmili and Christophe Caloz},
doi = {10.1109/TAP.2016.2632705},
issn = {0018-926X},
issue = {2},
journal = {IEEE Transactions on Antennas and Propagation},
keywords = {Dispersion engineering,electromagnetic metamaterials,metasurfaces,ultrafast electronics,ultrafast optics},
month = {2},
pages = {673-680},
title = {Dielectric Resonator Metasurface for Dispersion Engineering},
volume = {65},
url = {http://ieeexplore.ieee.org/document/7756403/},
year = {2017},
}
@article{Zou2017,
abstract = {We present a loss-gain equalized reconfigurable C-section analog signal processor (ASP) for dynamic radio analog signal processing (R-ASP). Such an ASP provides realtime tunable group delay response with all-pass transmission. We propose a lumped loss-gain implementation, where tuning and equalization are mostly easily achieved. A theoretical study derives the transfer function and the fundamental characteristics of the device. The ASP is finally experimentally demonstrated, first using a single loss-gain pair and finally a three cascaded loss-gain pair structure with full reconfigurability, where up-chirp and down-chirp group delays are shown for illustration. It is expected that this ASP will find wide applications in R-ASP systems requiring dynamic adaptability.},
author = {Lianfeng Zou and Shulabh Gupta and Christophe Caloz},
doi = {10.1109/TMTT.2016.2615920},
issn = {0018-9480},
issue = {2},
journal = {IEEE Transactions on Microwave Theory and Techniques},
keywords = {All-pass system,C-section,dispersion engineering,group delay,loss-gain pair,radio analog signal processing (R-ASP)},
month = {2},
pages = {555-564},
title = {Loss-Gain Equalized Reconfigurable C-Section Analog Signal Processor},
volume = {65},
url = {http://ieeexplore.ieee.org/document/7707395/},
year = {2017},
}
@article{Gupta2017,
abstract = {The Talbot effect is among the most fundamental wave propagation effect universal across the frequency spectrum and has been used extensively in both spatial and temporal domain for wide variety of applications. In this work, a generalized spatial Talbot effect is presented based on all-dielectric Huygens' metasurface, which when combined with the conventional Fractional Talbot effect, enables the scaling of aperture periodicities by any arbitrary real number. This is achieved by allowing and engineering the phase discontinuity distributions in space on the aperture using phase engineered all-dielectric reflectionless metasurfaces, in conjunction with free-space propagation. Specific implementations using Huygens' metasurfaces are proposed and their operation to achieve such non-integer scalings of the input aperture period is demonstrated using numerical results based on Fourier propagation method.},
author = {Shulabh Gupta},
doi = {10.1016/j.optcom.2016.10.011},
issn = {00304018},
journal = {Optics Communications},
keywords = {Fourier optics and signal processing,Metasurfaces,Phase-only filters,Phase-space in wave optics,Talbot and self-imaging effects},
month = {2},
pages = {25-29},
title = {Generalized spatial Talbot effect based on all-dielectric metasurfaces},
volume = {384},
url = {https://linkinghub.elsevier.com/retrieve/pii/S0030401816308744},
year = {2017},
}
@book{Gupta2017,
abstract = {Electromagnetic metamaterials (MTMs) are broadly defined as artificial effectively homogeneous electromagnetic structures with exotic properties not readily available in nature. They consist of an arrangement of subwavelength scattering particles emulating the atoms or molecules of real materials with enhanced properties. The scattering particles are typically arranged in a periodic lattice with the unit cell size p < λ g $ p\ll\lambda_g $, where λ g is the guided wavelength inside the MTM. Under such operating conditions, the structure behaves as 166a real material so that the electromagnetic waves sense the average, or effective, macroscopic and well-defined constitutive parameters, which depend on the nature of the unit cell. Their 2D counterparts are known as metasurfaces, which are thin layers of subwavelength resonant scatters that interact strongly with electromagnetic waves for achieving unique wavefront processing functionalities.},
author = {S. Gupta and M.A. Salem and C. Calozb},
doi = {10.1201/9781315364438},
editor = {Douglas H. Werner},
isbn = {9781315364438},
journal = {Broadband Metamaterials in Electromagnetics: Technology and Applications},
month = {7},
publisher = {Jenny Stanford Publishing},
title = {Broadband Metamaterials in Electromagnetics},
url = {https://www.taylorfrancis.com/books/9789814745697},
year = {2017},
}
@article{Gupta2016,
abstract = {Dispersion lies at the heart of real-time signal processing systems across the entire electromagnetic spectrum from radio to optics. However, the performance and applicability of such systems have been severely plagued by distortions due to the frequency-dependent nature of the amplitude response of the dispersive media. This frequency dependence is a fundamental consequence of causality, incarnated by Kramers-Kronig relations or, equivalently, by the Bode relations. In order to resolve this issue, we introduce here the concept of a perfect dispersive medium, which is a loss-gain medium characterized by a perfectly flat magnitude response along with a quasi-arbitrary phase response. This property results from equalized electric and magnetic dipole dispersions, whence the amplitude and phase of the transmission functions of the isolated loss and gain contributions become the inverse and remain the same, respectively, under sign reversal of the imaginary part of the equalized magnetodielectric polarizability. Such a perfect dispersive medium may be realized in the form of a metamaterial, and this paper demonstrates a corresponding stacked loss-gain metasurface structure for illustration. From a practical standpoint, perfect dispersive media may propel real-time signal processing technology to a new dimension, with a myriad of novel ultrafast communication, sensing, imaging, and instrumentation applications.},
author = {Shulabh Gupta and Christophe Caloz},
doi = {10.1109/TAP.2016.2623899},
issn = {0018-926X},
issue = {12},
journal = {IEEE Transactions on Antennas and Propagation},
keywords = {Chromatic dispersion,dispersion engineering,electromagnetic metamaterials,electromagnetic propagation,ultrafast electronics,ultrafast optics},
month = {12},
pages = {5299-5308},
title = {Perfect Dispersive Medium for Real-Time Signal Processing},
volume = {64},
url = {http://ieeexplore.ieee.org/document/7728011/},
year = {2016},
}
@inproceedings{Gupta2016,
abstract = {The Parity-Time pt symmetry properties of natural and perfect dispersive media are compared. It is shown that perfect dispersive media, characterized by a flat magnitude transmission response along with an arbitrary phase (dispersion) response, are inherently pt symmetric, whereas all naturally dispersive media are t asymmetric.},
author = {Shulabh Gupta and Christophe Caloz},
doi = {10.1109/APS.2016.7696466},
isbn = {978-1-5090-2886-3},
journal = {2016 IEEE International Symposium on Antennas and Propagation (APSURSI)},
month = {6},
pages = {1519-1520},
publisher = {IEEE},
title = {Parity-Time (PT) symmetry properties of natural and perfect dispersive media},
url = {http://ieeexplore.ieee.org/document/7696466/},
year = {2016},
}
@inproceedings{,
abstract = {The paper investigates pulse radiation from a leaky-wave antenna (LWA). A semi-analytical model is developed to compute the far-field produced by an arbitrary pulse excitation and this model is validated by full-wave simulation. The study demonstrates that both angular dispersion and time dispersion lead to pulse distortion and that their effect become increasingly problematic with increasing antenna length.},
author = {Nghia Nguyen-Trong and Christophe Fumeaux and Shulabh Gupta and Christophe Caloz},
doi = {10.1109/APS.2016.7695752},
isbn = {978-1-5090-2886-3},
journal = {2016 IEEE International Symposium on Antennas and Propagation (APSURSI)},
keywords = {dispersion,leaky-wave antennas,pulse radiation},
month = {6},
pages = {87-88},
publisher = {IEEE},
title = {Pulse radiation from a leaky-wave antenna},
url = {http://ieeexplore.ieee.org/document/7695752/},
year = {2016},
}
@inproceedings{Zou2016,
abstract = {The concept of dispersion code modulation (DCM) is introduced for enhancing spectral efficiency in wireless communications. An Nth order DCM modulation scheme splits data streams into N channels with distinct dispersion codes and hence increases the throughput by a factor N. A 2nd order DCMA system, based on physical models, is demonstrated.},
author = {Lianfeng Zou and Shulabh Gupta and Christophe Caloz},
doi = {10.1109/APS.2016.7696632},
isbn = {978-1-5090-2886-3},
journal = {2016 IEEE International Symposium on Antennas and Propagation (APSURSI)},
keywords = {Real-time analog signal processing (R-ASP),dispersion code modulation (DCM),dispersion engineering,phaser},
month = {6},
pages = {1851-1852},
publisher = {IEEE},
title = {Dispersion code modulation for enhanced spectral efficiency in wireless communications},
url = {http://ieeexplore.ieee.org/document/7696632/},
year = {2016},
}
@article{Taravati2016,
abstract = {We show that a continuously nonuniform coupled-line C-section phaser, as the limiting case of the step-discontinuous coupled-line multisection commensurate and non-commensurate phasers, provides enhanced bandwidth and diversity in real-time analog signal processing (R-ASP). The phenomenology of the component is explained in comparison with the step-discontinuous using multiple-reflection theory and a simple synthesis procedure is provided. The bandwidth enhancement results from the suppression of spurious group delay harmonics or quasi-harmonics, while the diversity enhancement results from the greater level of freedom provided by the continuous nature of the nonuniform profile of the phaser. These statements are supported by theoretical and experimental results.},
author = {Sajjad Taravati and Shulabh Gupta and Qingfeng Zhang and Christophe Caloz},
doi = {10.1109/LMWC.2016.2597188},
issn = {1531-1309},
issue = {9},
journal = {IEEE Microwave and Wireless Components Letters},
keywords = {C-section,group delay engineering,nonuniform transmission line,phaser,real-time analog signal processing},
month = {9},
pages = {663-665},
title = {Enhanced Bandwidth and Diversity in Real-Time Analog Signal Processing (R-ASP) Using Nonuniform C-Section Phasers},
volume = {26},
url = {http://ieeexplore.ieee.org/document/7551243/},
year = {2016},
}
@inproceedings{Gupta2016,
abstract = {An active micro-ring resonator is proposed as a 1-D implementation of a perfect dispersive medium concept, exhibiting a flat transmission response while maintaining a frequency dependent group delay response. Due to its non-TEM nature, the proposed devices are frequency scalable to high frequencies including THz and Optics.},
author = {Shulabh Gupta},
doi = {10.1109/PN.2016.7537979},
isbn = {978-1-5090-1373-9},
journal = {2016 Photonics North (PN)},
month = {5},
pages = {1-1},
publisher = {IEEE},
title = {Active micro-ring resonators as compact perfect dispersive devices},
url = {http://ieeexplore.ieee.org/document/7537979/},
year = {2016},
}
@article{Gupta2016,
abstract = {A single-order transmission diffraction grating based on dispersion engineered all-dielectric metasurfaces is proposed, and its wavelength discriminating properties have been theoretically described and confirmed using numerical simulations. The metasurface is designed using a 2D array of all-dielectric resonators, which emulates a Huygens' source configuration to achieve a perfect match to free space in broad bandwidth. Using a holey dielectric nanodisk structure as the unit cell, the resonant wavelength is tapered across the metasurface to engineer the wavelength-dependent spatial phase gradient, to emulate a dispersive prism. Consequently, different wavelengths are steered toward different directions and thus are discriminated on the output image plane. Due to the subwavelength periodicities involved, wavelength discrimination is achieved directly in the zeroth diffraction order of the device, unlike conventional diffraction gratings, thereby providing a high-efficiency wavelength discriminating device.},
author = {Shulabh Gupta},
doi = {10.1364/JOSAA.33.001641},
issn = {1084-7529},
issue = {8},
journal = {Journal of the Optical Society of America A},
month = {8},
pages = {1641},
title = {Single-order transmission diffraction gratings based on dispersion engineered all-dielectric metasurfaces},
volume = {33},
url = {https://opg.optica.org/abstract.cfm?URI=josaa-33-8-1641},
year = {2016},
}
@inproceedings{Zou2016,
abstract = {An adaptive Dispersion Code Multiple Access (DCMA) system is proposed and demonstrated using numerical calculations. Compared to conventional static DCMA, where channels between access points are fixed unless adaptive phasers are used, the proposed system employs a base-station which allows users with distinct but fixed phasers to form arbitrary adaptive channels between the access points. The base-station first records the channel responses in the sounding stage, and then uses this information to route the data between arbitrary user pairs in the communication stage.},
author = {L. Zou and S. Gupta and C. Caloz},
isbn = {9784885523038},
journal = {2015 International Symposium on Antennas and Propagation, ISAP 2015},
title = {Time-reversal based routing in Dispersion Code Multiple Access (DCMA)},
year = {2016},
}
@inproceedings{Khan2016,
abstract = {A spatial non-reciprocal and a non-gyrotropic structure is proposed based on coupled resonators used in conjunction with a magnetless isolator, and demonstrated using full-wave simulations.},
author = {B.A. Khan and S. Gupta and C. Caloz},
isbn = {9784885523038},
journal = {2015 International Symposium on Antennas and Propagation, ISAP 2015},
title = {Spatial nonreciprocal and nongyrotropic structure},
year = {2016},
}
@inproceedings{Gupta2015,
abstract = {A spatial phaser based on all-pass metasurfaces using Interconnected dielectric resonators is proposed for real-Time-Analog signal processing (R-ASP). The structure is simple to fabricate and is constructed from a single dielectric layer using standard laser hole drilling processing. Its all-pass transmission response along with its transmission delay characteristics are also demonstrated using rigorous coupled-wave analysis (RCWA).},
author = {Shulabh Gupta and Karim Achouri and Christophe Caloz},
doi = {10.1109/CAMA.2015.7428154},
isbn = {978-1-4673-9149-8},
journal = {2015 IEEE Conference on Antenna Measurements & Applications (CAMA)},
month = {11},
pages = {1-3},
publisher = {IEEE},
title = {All-pass metasurfaces based on interconnected dielectric resonators as a spatial phaser for real-time analog signal processing},
url = {http://ieeexplore.ieee.org/document/7428154/},
year = {2015},
}
@inproceedings{Gupta2015,
abstract = {The bit-error-rate (BER) performance of a 5 × 5 dispersion code multiple access system (DCMA) is numerically investigated assuming Chebyshev dispersion group delay coding. It is found that odd Chebyshev coding features lower BER than even Chevyshev coding between dispersion matched pairs within the DCMA system. This is the first study of a full DCMA communication system.},
author = {Shulabh Gupta and Lianfeng Zou and Mohamed A. Salem and Christophe Caloz},
doi = {10.1109/APS.2015.7304895},
isbn = {978-1-4799-7815-1},
issn = {15223965},
journal = {2015 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting},
month = {7},
pages = {1015-1016},
publisher = {IEEE},
title = {Bit-error-rate (BER) performance in dispersion code multiple access (DCMA)},
volume = {2015-Octob},
url = {https://ieeexplore.ieee.org/document/7304895/},
year = {2015},
}
@inproceedings{Gupta2015,
abstract = {An array of leaky-wave antennas (LWA) fed with a dispersive feeding network is proposed to decompose, in real-time, the spectral components of a broadband signal in two dimensions of space. Compared to typical real-time decomposition systems, which are restricted to one-dimensional decomposition, such a two-dimensional system can analyze faster signals and thus provide higher frequency resolution. The operation of the proposed structure is demonstrated using array-factor theory.},
author = {Shulabh Gupta and Christophe Caloz},
doi = {10.1109/APS.2015.7304400},
isbn = {978-1-4799-7815-1},
issn = {15223965},
journal = {2015 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting},
month = {7},
pages = {29-30},
publisher = {IEEE},
title = {Real-time 2-D spectral-decomposition using a leaky-wave antenna array with dispersive feeding network},
volume = {2015-Octob},
url = {https://ieeexplore.ieee.org/document/7304400},
year = {2015},
}
@inproceedings{Gupta2015,
abstract = {Two types of RTSAs are presented, which spectrally decompose a broadband electromagentic signal in space in real-time. The first system is based on an array of LWA fed using an array of phasers, where the dispersion of the phasers in conjunction with the natural frequency scanning of the leaky-wave antenna enable the 2-D frequency scan. The second system is a purely spatial system based on dispersive metasurface which operate on a incident wave and performs 2-D spectral decomposition. Their principle and basic characteristics are discussed in details.},
author = {S. Gupta and C. Caloz},
doi = {10.1109/ICEAA.2015.7297351},
isbn = {978-1-4799-7806-9},
journal = {2015 International Conference on Electromagnetics in Advanced Applications (ICEAA)},
keywords = {Arrays,Broadband antennas,Broadband communication,Dispersion,Leaky wave antennas,Real-time systems,Spectral analysis},
month = {9},
pages = {1412-1415},
publisher = {IEEE},
title = {Multi-dimensional real-time spectrum analysis for high-resolution signal processing},
url = {http://ieeexplore.ieee.org/document/7297351/},
year = {2015},
}
@article{Ding2015,
abstract = {A novel time-reversal subwavelength transmission technique, based on pulse-shaping circuits (PSCs), is proposed. This technique removes the need for complex or electrically large electromagnetic structures by generating channel diversity via pulse shaping instead of angular spectrum transformation. It is shown that, compared to our previous time-reversal system based on chirped delay lines, the PSC approach offers greater flexibility and larger possible numbers of channels, i.e., ultimately higher transmission throughput. The superiority of the PSC time-reversal system is also demonstrated experimentally.},
author = {Shuai Ding and Shulabh Gupta and Rui Zang and Lianfeng Zou and Bing-Zhong Wang and Christophe Caloz},
doi = {10.1109/TAP.2015.2445414},
issn = {0018-926X},
issue = {9},
journal = {IEEE Transactions on Antennas and Propagation},
keywords = {Time reversal,chirped delay lines (CDLs),sub-wavelength transmission},
month = {9},
pages = {4169-4174},
title = {Enhancement of Time-Reversal Subwavelength Wireless Transmission Using Pulse Shaping},
volume = {63},
url = {http://ieeexplore.ieee.org/document/7123608/},
year = {2015},
}
@article{Gupta2015,
abstract = {Generalized coupled-line all-pass phasers, based on cascaded C-sections (CCSs), cascaded coupled-lines (CCLs), and hybrid-cascaded (HC) coupled transmission-line sections, are presented and demonstrated using analytical, full-wave, and experimental results. It is shown that for N commensurate coupled-line sections, CCL and HC phasers exhibit N group-delay peaks per coupled-line section harmonic frequency band, in contrast to the CCS configuration, which exhibits only one peak within this band. It is also shown that for a given maximum achievable coupling-coefficient, the HC configuration provides the largest group-delay swing. A wave-interference analysis is finally applied to the various coupled-line phasers, explaining their unique group-delay characteristics based on physical wave-propagation mechanisms.},
author = {Shulabh Gupta and Qingfeng Zhang and Lianfeng Zou and Li Jun Jiang and Christophe Caloz},
doi = {10.1109/TMTT.2015.2397445},
issn = {0018-9480},
issue = {3},
journal = {IEEE Transactions on Microwave Theory and Techniques},
keywords = {All-pass networks,C-sections,D-sections,dispersion engineering,group-delay engineering,phasers,radio-analog signal processing (R-ASP)},
month = {3},
pages = {1007-1018},
title = {Generalized Coupled-Line All-Pass Phasers},
volume = {63},
url = {http://ieeexplore.ieee.org/document/7044609/},
year = {2015},
}
@inproceedings{Gupta2015,
abstract = {A backward and forward coupled ring transmission line all-pass phasers are presented, and their general characteristics, operation principles and typical group characteristics are discussed using ideal circuit simulations. The first configuration is based on contra-directional (backward) coupling, which is perfectly TEM, while the second configuration is based on non-TEM co-directional (forward) coupling, which is the radio-frequency counterpart of the optical ring resonator coupling. Compared to conventional end-connected coupled-line phasers, the group delay swings of the proposed phasers are inversely proportional to the involved coupling coefficients. They thus represent practically promising devices for high-resolution real-time radio.},
author = {S. Gupta and B.A. Khan and C. Caloz},
isbn = {9788890701856},
journal = {2015 9th European Conference on Antennas and Propagation, EuCAP 2015},
keywords = {Phasers,coupled-line couplers,optical ring resonators,radio analog signal processing (R-ASP),real-time radio},
title = {Forward/backward coupled ring based phasers for real-time signal processing},
year = {2015},
}
@article{Achouri2015,
abstract = {The paper presents partial overview of the mathematical synthesis and the physical realization of metasurfaces, and related illustrative examples. The synthesis consists in determining the exact tensorial surface susceptibility functions of the metasurface, based on generalized sheet transition conditions, while the realization deals with both metallic and dielectric scattering particle structures. The examples demonstrate the capabilities of the synthesis and realization techniques, thereby showing the plethora of possible metasurface field transmission and subsequent applications. The first example is the design of two diffraction engineering birefringent metasurfaces performing polarization beam splitting and orbital angular momentum multiplexing, respectively. Next, we discuss the concept of the electromagnetic remotely controlled metasurface spatial processor, which is an electromagnetic linear switch based on destructive interferences. Then, we introduce a non-reciprocal non-gyrotropic metasurface using a pick-up circuit radiator (PCR) architecture. Finally, the implementation of all-dielectric metasurfaces for frequency dispersion engineering is discussed.},
author = {Karim Achouri and Bakthiar Ali Khan and Shulabh Gupta and Guillaume Lavigne and Mohamed Ahmed Salem and Christophe Caloz},
doi = {10.1051/epjam/2015016},
editor = {Argyropoulos Christos and Monti Alessio},
issn = {2272-2394},
journal = {EPJ Applied Metamaterials},
keywords = {Birefringence,Frequency dispersion engineering,Metamaterial switch,Metasurface synthesis,Non-reciprocal metadevice,Orbital angular momentum,Refraction},
month = {1},
pages = {12},
title = {Synthesis of electromagnetic metasurfaces: principles and illustrations},
volume = {2},
url = {http://epjam.edp-open.org/10.1051/epjam/2015016},
year = {2015},
}
@inproceedings{Zou2015,
abstract = {Some emerging applications of R-ASP require the radio systems to adapt to dynamic environments. This cannot be achieved using phasers with fixed group delay profiles. Therefore, we introduce here a gain-loss loaded C-section phaser featuring real-Time tunability, or reconfigurability, in group delay. This phaser exhibits an all-pass response all the way across its tuning range thanks to a paired and equalized gain-loss C-section unit. A numerical example is provided, where reconfigurability is achieved by tuning the gain-loss pair of the different gain-loss C-section units of the phaser.},
author = {Lianfeng Zou and Shulabh Gupta and Christophe Caloz},
doi = {10.1109/APMC.2015.7413491},
isbn = {978-1-4799-8765-8},
journal = {2015 Asia-Pacific Microwave Conference (APMC)},
month = {12},
pages = {1-3},
publisher = {IEEE},
title = {Reconfigurable phaser using gain-loss C-sections for radio analog signal processing (R-ASP)},
volume = {3},
url = {http://ieeexplore.ieee.org/document/7413491/},
year = {2015},
}
@article{Ma2015,
abstract = {This paper proposes a general characterization of one dimensional multiple periodic (MP) structures for electromagnetic transmission and radiation. Studies are conducted from three aspects: Firstly, the dispersion relations of non-dispersive (conventional) and dispersive (composite right/left-handed (CRLH)) materials are analyzed. Regarding each category of materials, detailed analyses for distributed layered media and lumped circuits are presented. Through studies, we found that the periodicity increase opens up multiple stopbands. According to our physical explanations and numerical results, the relation between stopbands and periodicity is clarified. Additionally, the periodicity increase also reduces the separation distance of space harmonic modes along the phase constant axis in the dispersion diagram. Thus, more space harmonic modes are excited in the radiation. This phenomenon results in simultaneous right-and left-handed radiation and multiple radiation beams. Secondly, mathematical formulas for the general dispersion relation and the general Bragg condition of the MP structures are derived. The formulas help to indicate the locations of stopbands and engineer the dispersion relation. Thirdly, applications of the MP structures to phase reversal (PR) antennas are presented. Both transmission and radiation characteristics of the MP structures are validated by the PR antennas experimentally. Single, double and triple periodic structures are comparatively studied.},
author = {Zi Long Ma and Li Jun Jiang and Shulabh Gupta and Wei E.I. Sha},
doi = {10.1109/TAP.2014.2366785},
issn = {0018-926X},
issue = {1},
journal = {IEEE Transactions on Antennas and Propagation},
keywords = {Dispersion analysis,dispersive structure,leaky-wave antenna,multi-beam radiation,multiple periodic structure,non-dispersive structure,phase reversal antenna},
month = {1},
pages = {113-121},
title = {Dispersion Characteristics Analysis of One Dimensional Multiple Periodic Structures and Their Applications to Antennas},
volume = {63},
url = {http://ieeexplore.ieee.org/document/6945355/},
year = {2015},
}
@inproceedings{Gupta2014,
abstract = {The beam-switching characteristics of Magneto-Electric (ME) dipole antenna array is presented based on differentially exciting the two ports of the array with different polarities. The proposed principle is demonstrated using full-wave simulations that the depending on the polarity of the two excitations, either a magnetic-dipole or an electric-dipole radiation can be selectively achieved.},
author = {Shulabh Gupta and Li Jun Jiang},
doi = {10.1109/URSIGASS.2014.6929165},
isbn = {978-1-4673-5225-3},
journal = {2014 XXXIth URSI General Assembly and Scientific Symposium (URSI GASS)},
month = {8},
pages = {1-3},
publisher = {IEEE},
title = {Beam-switchable Magneto-Electric antenna array based on composite right/left-handed (CRLH) structures},
url = {http://ieeexplore.ieee.org/document/6929165/},
year = {2014},
}
@article{Gupta2014,
abstract = {A closed-form iterative procedure for synthesizing quasi-arbitrary phase responses with cascaded microwave C-section all-pass phasers is presented. The synthesis consists in mapping the transmission poles of the cascaded C-section structure onto the transmission poles of the specified transfer function, where the latter poles are computed using a closed-form polynomial generation method. The real and complex transmission poles of the specified transfer function are realized using C-sections of different lengths and different couplings coefficients. The proposved synthesis is validated by both full-wave analysis and measured multilayer prototypes.},
author = {Shulabh Gupta and Dimitrios Sounas and Qingfeng Zhang and Christophe Caloz},
doi = {10.1002/cta.1916},
issn = {00989886},
issue = {12},
journal = {International Journal of Circuit Theory and Applications},
keywords = {All-pass networks,Analog signal processing,Dispersive delay structures,Group delay engineering,Phasers},
month = {12},
pages = {1228-1245},
title = {All-pass dispersion synthesis using microwave C-sections},
volume = {42},
url = {https://onlinelibrary.wiley.com/doi/10.1002/cta.1916},
year = {2014},
}
@inproceedings{Chen2014,
abstract = {A 2-D slot array structure to achieve near-field beam focusing, with a linear polarization, is proposed and demonstrated using full-wave simulations. The proposed structure has a negligible cross-polarization and its far-field gain is lower by 10 dB compared to the non-focus case, indicating a good focusing in the near-field of the structure.},
author = {Meng Lin Chen and Shulabh Gupta and Zi Long Ma and Li Jun Jiang},
doi = {10.1109/APS.2014.6904850},
isbn = {978-1-4799-3540-6},
issn = {15223965},
journal = {2014 IEEE Antennas and Propagation Society International Symposium (APSURSI)},
month = {7},
pages = {1047-1048},
publisher = {IEEE},
title = {Linearly polarized near field focused slot-array waveguide},
url = {https://ieeexplore.ieee.org/document/6904850},
year = {2014},
}
@inproceedings{Gupta2014,
abstract = {A meandered version of the phase-reversal leaky-wave antenna is introduced to reduce the permittivity requirement εeff > 4 for single-beam full-space scanning.},
author = {Shulabh Gupta and Li Jun Jiang and Christophe Caloz},
doi = {10.1109/APS.2014.6904363},
isbn = {978-1-4799-3540-6},
issn = {15223965},
journal = {2014 IEEE Antennas and Propagation Society International Symposium (APSURSI)},
month = {7},
pages = {63-64},
publisher = {IEEE},
title = {Reduced-permittivity meandered single-beam full-space scanning phase-reversal leaky-wave antenna},
url = {http://ieeexplore.ieee.org/document/6904363/},
year = {2014},
}
@article{Gupta2014,
abstract = {A passive chipless radio-frequency identification (RFID) tag based on a log-periodic (LP) dipole array is proposed, where the tailorable bandrejection property of the LP aperture is utilised to realise a large number of codes. The proposed tag principle is successfully validated by measurements, where the absence and presence of the band-rejection is shown to carry the bit information. Its fabrication simplicity is also demonstrated by its implementation on a flexible substrate. Finally, two different tag formation schemes, based on a specific set of resonance suppressions, are discussed in detail. © 2014 The Institution of Engineering and Technology.},
author = {S. Gupta and Gui Jun Li and R.C. Roberts and Li Jun Jiang},
doi = {10.1049/el.2013.4253},
issn = {0013-5194},
issue = {5},
journal = {Electronics Letters},
month = {2},
pages = {339-341},
title = {Log‐periodic dipole array antenna as chipless RFID tag},
volume = {50},
url = {https://onlinelibrary.wiley.com/doi/10.1049/el.2013.4253},
year = {2014},
}
@inproceedings{Ma2014,
abstract = {In this paper, the generalized analysis and novel application of the multiple periodic (MP) structure are proposed. Both transmission and radiation performances of one dimensional MP structures are studied. The dispersion relations are analyzed from both layered media (distributive) and lumped circuits aspects. Regarding each aspect, both non-dispersive (conventional) and dispersive (composite right/left-handed (CRLH)) materials are discussed. It is found that with the increase of the periodicity, multiple stopbands are open up due to the reflections. Meanwhile the space harmonic modes' separation distance is reduced in the dispersion diagrams. It leads to simultaneously dualistic (right- and left-handed) radiation performance and multi-beam property, and more abundant radiation modes are excited at relatively lower frequencies comparing with conventional periodic structures. A general dispersion relation formula and a general Bragg condition for MP structures are derived. The dispersion relation is simply described by the former, and the latter helps to indicate the stopbands locations and engineer the dispersion relation consequently. Applications of MP structures to phase reversal (PR) antennas are also presented in this paper. They experimentally verifies both transmission and radiation characteristics of MP structures. In each analysis, single (SP), double (DP) and triple periodic (TP) structures are presented and compared. This work would also contribute to designs of multi-band devices.},
author = {Z.L. Ma and L.J. Jiang and S. Gupta and W.E.I. Sha},
isbn = {9781934142288},
issn = {19317360},
journal = {Progress in Electromagnetics Research Symposium},
title = {The multiple periodic structure antenna design},
year = {2014},
}
@inproceedings{Gupta2014,
abstract = {Two type of planar leaky-wave antennas are presented which are capable of providing combined electric and magnetic-dipole radiation responses from a single electromagnetic structure, leading to exotic radiation pattern characteristics. Their principle and radiation characteristics are discussed in details.},
author = {S. Gupta and C. Caloz and L. J. Jiang},
doi = {10.1109/APWC.2014.6905573},
isbn = {978-1-4673-5692-3},
journal = {2014 IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications (APWC)},
month = {8},
pages = {608-611},
publisher = {IEEE},
title = {Traveling-wave antennas with exotic radiation patterns},
url = {http://ieeexplore.ieee.org/document/6905573/},
year = {2014},
}
@article{Paradis2014,
abstract = {A hybrid-cascade (HC) coupled-line phaser configuration is presented to synthesize enhanced group delay responses for high-resolution radio-analog signal processing. Using exact analytical transfer functions, the superiority of HC coupled-line phasers over conventional transversally cascaded C-section phasers is demonstrated and verified using full-wave simulations. © 2014 Wiley Periodicals, Inc.},
author = {Thomas Paradis and Shulabh Gupta and Qingfeng Zhang and Li J. Jiang and Christophe Caloz},
doi = {10.1002/mop.28626},
issn = {08952477},
issue = {11},
journal = {Microwave and Optical Technology Letters},
keywords = {analog signal processing,couple-line couplers,dispersion engineering,group delay engineering,phasers},
month = {11},
pages = {2502-2504},
title = {Hybrid-cascade coupled-line phasers for high-resolution radio-analog signal processing},
volume = {56},
url = {https://onlinelibrary.wiley.com/doi/10.1002/mop.28626},
year = {2014},
}
@article{Gupta2014,
abstract = {A planar magnetoelectric (ME) dipole antenna array is proposed and demonstrated by both full-wave analysis and experiments. The proposed structure leverages the operation of composite right/left-handed transmission lines under balanced conditions to form high-gain magnetic radiators, combined with radial conventional electric radiators, where the overall structure is excited by a single differential feed. The traveling-wave-type nature of the proposed ME-dipole antenna enables the formation of directive arrays with high-gain characteristics and scanning capability. Peak gains of 10.84 dB and 5.73 dB are demonstrated for the electric dipole and magnetic-dipole radiation components, respectively. © 1963-2012 IEEE.},
author = {Shulabh Gupta and Li Jun Jiang and Christophe Caloz},
doi = {10.1109/TAP.2014.2320531},
issn = {0018-926X},
issue = {7},
journal = {IEEE Transactions on Antennas and Propagation},
keywords = {Antenna array,composite right/left-handed (CRLH) transmission li,frequency beamscanning,leaky-wave antenna,magnetoelectric (ME) dipole,traveling-wave structure},
month = {7},
pages = {3613-3622},
title = {Magnetoelectric Dipole Antenna Arrays},
volume = {62},
url = {http://ieeexplore.ieee.org/document/6808488/},
year = {2014},
}
@article{Gupta2014,
abstract = {The radiation principle of traveling-wave-type phase-reversal antennas is explained in detail, unveiling the presence of magnetic-dipole radiation in addition to well-known electric dipole radiation. It is pointed out that such magnetic-dipole radiation is specific to the case of traveling-wave phase-reversal antennas, whereas only electric-dipole radiation exists in resonant-type phase-reversal antennas. It is shown that a phase-reversal traveling-wave antenna alternately operates as an array of magnetic dipoles and an array of electric dipoles during a time-harmonic period. This radiation mechanism is confirmed through both full-wave and experimental results. © 2014 IEEE.},
author = {Shulabh Gupta and Li Jun Jiang and Christophe Caloz},
doi = {10.1109/LAWP.2014.2317739},
issn = {1536-1225},
journal = {IEEE Antennas and Wireless Propagation Letters},
keywords = {Balanced transmission line,full-space scanning,leaky-wave antenna,magneto-electric antennas,phase-reversal},
pages = {786-789},
title = {Unveiling Magnetic Dipole Radiation in Phase-Reversal Leaky-Wave Antennas},
volume = {13},
url = {http://ieeexplore.ieee.org/document/6799203/},
year = {2014},
}
@article{Zhang2014,
abstract = {We propose an exact closed-form synthesis method for the design of broadband dispersive delay structures (DDSs) formed by the series connection of commensurate all-pass C- and D-sections. In this method, the transfer function synthesis problem is converted into a Hurwitz polynomial generation problem, where the real roots correspond to C-sections and the complex roots correspond to D-sections. Several design examples are provided to illustrate the proposed synthesis method. A prototype is implemented in strip-line configuration and fabricated in LTCC technology, and the measured response is in good agreement with the prescribed and full-wave responses. © 2013 2013 Wiley Periodicals, Inc.},
author = {Qingfeng Zhang and Shulabh Gupta and Christophe Caloz},
doi = {10.1002/mmce.20764},
issn = {10964290},
issue = {3},
journal = {International Journal of RF and Microwave Computer-Aided Engineering},
keywords = {C-section,D-section,DDSs,all-pass,broadband,dispersion engineering,group delay synthesis},
month = {5},
pages = {322-331},
title = {Synthesis of broadband dispersive delay structures formed by commensurate C- and D-sections},
volume = {24},
url = {https://onlinelibrary.wiley.com/doi/10.1002/mmce.20764},
year = {2014},
}
@inproceedings{Gupta2013,
abstract = {The bi-directional radiation characteristics and corresponding performance under high CW power of a planar log-periodic (LP) antenna is investigated experimentally and demonstrated within a wide bandwidth. Two LP configurations are designed and built on 20 mil and 60 mil substrates with tapered and multi-section microstrip feeds, respectively. Results show that the developed LP antennas are able to handle at least 50 W and 200 W of CW power at 5 GHz. © 2013 IEEE.},
author = {Shulabh Gupta and Maxwell Perez and Joseph R. Mruk and Matthew J. Radway and Dejan S. Filipovic},
doi = {10.1109/APS.2013.6711210},
isbn = {978-1-4673-5317-5},
issn = {15223965},
journal = {2013 IEEE Antennas and Propagation Society International Symposium (APSURSI)},
month = {7},
pages = {1100-1101},
publisher = {IEEE},
title = {Decade bandwidth bidirectional planar log-periodic antennas and their performance under low and high continuous-wave (CW) input power},
url = {http://ieeexplore.ieee.org/document/6711210/},
year = {2013},
}
@inproceedings{Gupta2013,
abstract = {A passive chipless Radio-frequency identification (RFID) tag is proposed based on the tailorable band-rejection property of the log-periodic (LP) antennas. The proposed tag principle is successfully demonstrated using full-wave simulations, where the absence and presence of the band-rejection in VSWR and thus radiation gain, is shown to carry the bit information. Due to the large number of dipole radiators on the LP aperture, the proposed tag can easily support large number of codes, providing a potential solution for limited number of bits in conventional chipless tags. © 2013 IEEE.},
author = {Shulabh Gupta and Li Jun Jiang},
doi = {10.1109/APS.2013.6711220},
isbn = {978-1-4673-5317-5},
issn = {15223965},
journal = {2013 IEEE Antennas and Propagation Society International Symposium (APSURSI)},
month = {7},
pages = {1120-1121},
publisher = {IEEE},
title = {Chipless RFID tags based on multiple band-rejected planar log-periodic antennas},
url = {http://ieeexplore.ieee.org/document/6711220/},
year = {2013},
}
@inproceedings{Ma2013,
abstract = {The wave-propagation characteristics in a one-dimensional multiple-periodic (MP) Composite right/left-handed (CRLH) structures is presented, where it is found that an increase in the number of unit cells in each supercell leads to new passbands and stopbands. To understand this phenomenon, the network parameters are employed for the theoretical analysis. Detailed dispersion characteristics and the relation between passbands and sub-periodicities are investigated using both analytical and full-wave results, and the reasons for their emergence is qualitatively discussed. Besides, its application to multi-band leaky-wave radiators is also suggested. © 2013 IEEE.},
author = {Zi Long Ma and Li Jun Jiang and Shulabh Gupta and Wei E.I. Sha},
doi = {10.1109/APS.2013.6710978},
isbn = {978-1-4673-5317-5},
issn = {15223965},
journal = {2013 IEEE Antennas and Propagation Society International Symposium (APSURSI)},
month = {7},
pages = {636-637},
publisher = {IEEE},
title = {One dimensional multiple periodic composite right/left handed (CRLH) structures},
url = {http://ieeexplore.ieee.org/document/6710978/},
year = {2013},
}
@article{Caloz2013,
abstract = {Today's exploding demand for faster, more reliable, and ubiquitous radio systems in communication, instrumentation, radar, and sensors poses unprecedented challenges in microwave and millimeter-wave engineering. Recently, the predominant trend has been to place an increasing emphasis on digital signal processing (DSP). However, while offering device compactness and processing flexibility, DSP suffers fundamental drawbacks, such as high-cost analog-digital conversion, high power consumption, and poor performance at high frequencies. © 2000-2012 IEEE.},
author = {Christophe Caloz and Shulabh Gupta and Qingfeng Zhang and Babak Nikfal},
doi = {10.1109/MMM.2013.2269862},
issn = {1527-3342},
issue = {6},
journal = {IEEE Microwave Magazine},
month = {9},
pages = {87-103},
title = {Analog Signal Processing: A Possible Alternative or Complement to Dominantly Digital Radio Schemes},
volume = {14},
url = {http://ieeexplore.ieee.org/document/6588371/},
year = {2013},
}
@article{,
abstract = {This paper presents a rigorous and intuitive wave-interference explanation of group-delay dispersion in resonators. It considers both one-port and two-port lossless and lossy resonators under the complementary frequency-domain and time-domain perspectives. The reasons for the group-delay dispersive nature of a resonator and for the phenomenon of negative group delay (superluminality) in a lossy resonator are clearly explained in terms of the constructive and destructive interferences of multiply refl ected pulses.},
author = {Qingfeng Zhang and D. L. Sounas and S. Gupta and C. Caloz},
doi = {10.1109/MAP.2013.6529352},
issn = {1045-9243},
issue = {2},
journal = {IEEE Antennas and Propagation Magazine},
keywords = {Dispersion,Group delay,Interference,Pulse propagation,Resonators,Superluminality},
month = {4},
pages = {212-227},
title = {Wave-Interference Explanation of Group-Delay Dispersion in Resonators [Education Column]},
volume = {55},
url = {http://ieeexplore.ieee.org/document/6529352/},
year = {2013},
}
@inproceedings{Gupta2013,
abstract = {A new magneto-electric (ME) dipole antenna array is proposed which provides a combined electric- and magnetic-dipole response in a planar configuration. The proposed structure is based on Composite Right/Left-Handed (CRLH) transmission lines, which is differentially fed and operated in the zeroth-order regime to provide maximal gain for the combined radiators. The basic principle of the proposed ME-dipole antenna is discussed and demonstrated with full-wave simulation results. © 2013 IEEE.},
author = {S. Gupta and L. J. Jiang and C. Caloz},
doi = {10.1109/APWC.2013.6624904},
isbn = {978-1-4673-5689-3},
journal = {2013 IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications (APWC)},
month = {9},
pages = {765-766},
publisher = {IEEE},
title = {Magneto-electric dipole antenna based on differentially-excited Composite Right/Left-Handed (CRLH) transmission lines},
url = {https://ieeexplore.ieee.org/document/6624904},
year = {2013},
}
@inproceedings{Gupta2013,
abstract = {A new C-section phasers based on folded coupled-line couplers has been proposed for high-resolution analog signal processing (ASP). The folded configuration of the coupled-line coupler provides a tight coupling in a planar configuration between the input and the coupled port, using sections of relatively small coupling values. It subsequently provides a larger group delay swing in the corresponding C-section phaser required for enhanced resolution ASP. The proposed phaser is demonstrated using full-wave simulations. © 2013 IEEE.},
author = {S. Gupta and L. J. Jiang and C. Caloz},
doi = {10.1109/ICEAA.2013.6632347},
isbn = {978-1-4673-5707-4},
journal = {2013 International Conference on Electromagnetics in Advanced Applications (ICEAA)},
month = {9},
pages = {771-773},
publisher = {IEEE},
title = {Enhanced-resolution folded C-section phaser},
url = {http://ieeexplore.ieee.org/document/6632347/},
year = {2013},
}
@inproceedings{Caloz2012,
abstract = {Microwave and millimeter-wave analog signal processing (ASP) is a novel paradigm with great promise for high-speed microwave and millimeter-wave systems. The authors' group has done intensive research in this area over the past few years and presents here an overview of their results, which cover phaser technologies, phaser synthesis techniques and various applications. © 2012 IEEE.},
author = {Christophe Caloz and Shulabh Gupta and Babak Nikfal and Qingfeng Zhang},
doi = {10.1109/APMC.2012.6421705},
isbn = {978-1-4577-1332-3},
journal = {2012 Asia Pacific Microwave Conference Proceedings},
keywords = {Analog signal processing (ASP),C-sections,D-sections,cross-coupled structures,dispersion engineering,frequency meters,phaser synthesis,phasers,radio-frequency identifiers,real-time spectrum analyzers,realtime Fourier transformers,spectrum sniffers},
month = {12},
pages = {691-692},
publisher = {IEEE},
title = {Analog signal processing (ASP) for high-speed microwave and millimeter-wave systems},
url = {http://ieeexplore.ieee.org/document/6421705/},
year = {2012},
}
@article{Gupta2012,
abstract = {A novel dispersive delay structure (DDS) based on a composite right/left-handed (CRLH)-CRLH coupler is proposed and demonstrated by both full-wave and experimental results. The experimental prototypes are compact and shielded multilayer DDSs implemented in low-temperature co-fired ceramics technology. Compared to the conventional all-pass C-section DDS, the proposed CRLH C-section DDS exhibit a larger group-delay swing, which leads to higher resolution in analog signal processing applications, as a result of their higher coupling capability. Moreover, they feature a larger bandwidth and a smaller size. A generalized wave-interference analysis is presented to both rigorously derive the transfer functions and group-delay characteristics of C-section DDSs and provide deeper insight into their operating mechanisms in both their left-and right-handed regimes. © 2012 IEEE.},
author = {Shulabh Gupta and Dimitrios L. Sounas and Hoang Van Nguyen and Qingfeng Zhang and Christophe Caloz},
doi = {10.1109/TMTT.2012.2224362},
issn = {0018-9480},
issue = {12},
journal = {IEEE Transactions on Microwave Theory and Techniques},
keywords = {Analog signal processing (ASP),C-section all-pass networks,composite right/left-handed (CRLH) transmission li,dispersion engineering,dispersive delay structure (DDS),group-delay engineering,low-temperature co-fired ceramics (LTCC)},
month = {12},
pages = {3939-3949},
title = {CRLH–CRLH C-Section Dispersive Delay Structures With Enhanced Group-Delay Swing for Higher Analog Signal Processing Resolution},
volume = {60},
url = {http://ieeexplore.ieee.org/document/6355643/},
year = {2012},
}
@article{Nikfal2012,
abstract = {The concept of real-time spectrum sniffing - featuring a simple and low-cost circuit architecture with straightforward frequency scalability - is introduced for cognitive radio systems. A stepped group-delay phaser is proposed and demonstrated to eliminate the issue of frequency resolution limitation due to the dispersion spreading induced by conventional phasers. © 2001-2012 IEEE.},
author = {Babak Nikfal and Daniel Badiere and Morris Repeta and Brad Deforge and Shulabh Gupta and Christophe Caloz},
doi = {10.1109/LMWC.2012.2219514},
issn = {1531-1309},
issue = {11},
journal = {IEEE Microwave and Wireless Components Letters},
keywords = {Dispersive delay structures,frequency discrimination,phaser,short-range communications,spectrum sniffing},
month = {11},
pages = {601-603},
title = {Distortion-Less Real-Time Spectrum Sniffing Based on a Stepped Group-Delay Phaser},
volume = {22},
url = {http://ieeexplore.ieee.org/document/6319368/},
year = {2012},
}
@inproceedings{Gupta2012,
abstract = {A novel dispersive delay structure (DDS) based on a CRLH-CRLH coupler is proposed, analyzed using a quasi-TEM transmission line model, and demonstrated by both full-wave and experimental results. Compared to conventional all-pass C-sections, the proposed CRLH based DDS provides a much larger group delay swing, thereby leading to much higher resolution in analog signal processing (ASP) applications, due to its capability of providing extremely high coupling levels. © 2012 IEEE.},
author = {Shulabh Gupta and Christophe Caloz},
doi = {10.1109/MWSYM.2012.6259431},
isbn = {978-1-4673-1088-8},
issn = {0149645X},
journal = {2012 IEEE/MTT-S International Microwave Symposium Digest},
keywords = {All-pass networks,Analog signal processing (ASP),Composite right/lefthanded (CRLH) transmission lin,Dispersion engineering,Dispersive delay structures (DDS)},
month = {6},
pages = {1-3},
publisher = {IEEE},
title = {Highly dispersive delay structure exploiting the tight coupling property of the CRLH-CRLH coupler for enhanced resolution analog signal processing},
url = {http://ieeexplore.ieee.org/document/6259431/},
year = {2012},
}
@article{Zhang2012,
abstract = {An exact closed-form synthesis method is proposed for the design of narrowband reflection-type (mono-port) phasers with arbitrary prescribed group-delay responses. The proposed synthesis technique consists in three steps. First, it transforms the phase problem from the bandpass domain to the low-pass domain using a one-port ladder network, where a mathematical synthesis is performed via a Hurwitz polynomial. Second, it transforms the synthesized low-pass network back to the bandpass domain for implementation in a specific technology. Third, it uses an iterative post-distortion correction technique to compensate for distributed effects over the broader bandwidth required. The proposed synthesis method is verified by both full-wave analysis and experiment where the synthesized bandpass network is realized in an iris-coupled waveguide configuration. © 1963-2012 IEEE.},
author = {Qingfeng Zhang and Shulabh Gupta and Christophe Caloz},
doi = {10.1109/TMTT.2012.2198486},
issn = {0018-9480},
issue = {8},
journal = {IEEE Transactions on Microwave Theory and Techniques},
keywords = {Analog signal processing,Hurwitz polynomial,dispersive delay structure (DDS),group-delay engineering,phaser},
month = {8},
pages = {2394-2402},
title = {Synthesis of Narrowband Reflection-Type Phasers With Arbitrary Prescribed Group Delay},
volume = {60},
url = {http://ieeexplore.ieee.org/document/6214999/},
year = {2012},
}
@article{Gupta2012,
abstract = {The principle of group delay swing enhancement in a transmission-line all-pass network using the combined coupling and dispersion boosting properties of a ferromagnetic substrate is proposed; full-wave verified and experimentally demonstrated using ferrite substrates as a proof of concept. The proposed group delay swing enhanced structures are compact in size, exhibiting a larger dispersion per unit area compared with other alternative techniques for dispersion enhancement, and a magnetically tunable group delay swing. The proposal to suppress the requirement of an external magnet is discussed based on self-biased ferromagnetic nanowire substrates and expected improvements are further pointed out. © 2012 Wiley Periodicals, Inc.},
author = {Shulabh Gupta and Louis-Philippe Carignan and Christophe Caloz},
doi = {10.1002/mop.26658},
issn = {08952477},
issue = {3},
journal = {Microwave and Optical Technology Letters},
keywords = {All-pass circuits,Analog signal processing,Dispersive structure,Ferrimagnetic materials,Group delay},
month = {3},
pages = {589-593},
title = {Group delay swing enhancement in transmission-line all-pass networks using coupling and dispersion boosting ferrimagnetic substrate},
volume = {54},
url = {https://onlinelibrary.wiley.com/doi/10.1002/mop.26658},
year = {2012},
}
@article{Nikfal2012,
abstract = {A low-cost analog pulse compression technique is proposed and experimentally demonstrated for a quasi-gaussian pulse. This technique consists in multiplying the pulse to compress with an auxiliary baseband gaussian pulse, which results in a compression of √2, and re-injecting this pulse n times around a loop including an amplifier, a delay line and an isolator, so as to achieve a compression factor of √1+n. In the experiment, a pulse width compression by a factor of 2.85 is achieved after the ninth turn, in good agreement with the theory. Due to its inherent analog nature, the proposed system is flexible, easy to implement, frequency scalable and capable to handle ultra-wideband signals. © 2006 IEEE.},
author = {Babak Nikfal and Shulabh Gupta and Christophe Caloz},
doi = {10.1109/LMWC.2012.2184274},
issn = {1531-1309},
issue = {3},
journal = {IEEE Microwave and Wireless Components Letters},
keywords = {Dispersive delay structures (DDS),loop systems,pulse compression,pulse generation,ultra-wideband (UWB) technology},
month = {3},
pages = {150-152},
title = {Low-Cost Analog Pulse Compression Technique Based on Mixing With an Auxiliary Pulse},
volume = {22},
url = {http://ieeexplore.ieee.org/document/6157652/},
year = {2012},
}
@article{Horii2012,
abstract = {A compact multilayer non-commensurate C-section dispersive delay structure (DDS) is proposed for analog signal processing (ASP) applications. In contrast to a previously reported C-section DDS, which was uniplanar and used edge-coupled C-sections, this DDS is based on broadside-coupled C-sections, and hence achieves a much larger ratio of group delay swing to frequency bandwidth, leading to higher ASP resolution. Moreover, it is much more compact, while maintaining acceptable insertion loss. After a parametric characterization of a mono-block commensurate multilayer DDS, with varied strip widths, two multiblock non-commensurate DDSs with linear group delay slopes are demonstrated by full-wave simulation and experimental low-temperature co-fired ceramics results. The proposed DDS exhibits a significant footprint reduction factor of around 7 compared to its uniplanar edge-coupled counterpart. © 2006 IEEE.},
author = {Yasushi Horii and Shulabh Gupta and Babak Nikfal and Christophe Caloz},
doi = {10.1109/LMWC.2011.2176476},
issn = {1531-1309},
issue = {1},
journal = {IEEE Microwave and Wireless Components Letters},
keywords = {All-pass networks,analog signal processing (ASP),dispersion engineering,dispersive delay structures (DDSs),group delay engineering,low-temperature co-fired ceramics (LTCC) technolog},
month = {1},
pages = {1-3},
title = {Multilayer Broadside-Coupled Dispersive Delay Structures for Analog Signal Processing},
volume = {22},
url = {http://ieeexplore.ieee.org/document/6107590/},
year = {2012},
}
@inproceedings{Gupta2011,
abstract = {An amplitude equalized C-section based all-pass dispersive delay structure (DDS) is proposed and experimentally demonstrated by cascading the DDS with a resistive transmission line network. Using such resistive networks, the frequency dependent dielectric and conductor losses of the transmission lines are equalized. This leads to a flat transmission response of the DDSs which is critical for efficient processing and detection of ultrafast time-domain signals using various analog signal processing (ASP) techniques. © 2011 IEEE.},
author = {Shulabh Gupta and Yasushi Horii and Babak Nikfal and Christophe Caloz},
doi = {10.1109/TELSKS.2011.6143225},
isbn = {978-1-4577-2019-2},
journal = {2011 10th International Conference on Telecommunication in Modern Satellite Cable and Broadcasting Services (TELSIKS)},
keywords = {Analog signal processing,amplitude equalizers,dispersion engineering,dispersive delay structure},
month = {10},
pages = {379-382},
publisher = {IEEE},
title = {Amplitude equalized transmission line dispersive delay structure for analog signal processing},
volume = {2},
url = {http://ieeexplore.ieee.org/document/6143225/},
year = {2011},
}
@inproceedings{Gupta2011,
abstract = {A novel mechanism based on corrugations is proposed to control undesired oblique wave propagation inside a parallel plate waveguide existing in the presence of 45 polarized radiating slots. The improvement in the near-field aperture distribution is demonstrated experimentally by aperture field measurement in a new slot array antenna incorporating these corrugations. Only marginal directivity improvement is observed and the measured gain is lower than in the original antenna (without corrugations) due to larger dissipative loss in the structure. However, it is argued that the proposed corrugated structure has the potential to improve the overall 2D slot array antenna performance after further optimization. © 2011 IEEE.},
author = {S. Gupta and C. Caloz and M. Samardzija and S. Yuanfeng and J. Hirokawa and M. Ando},
doi = {10.1109/APS.2011.5997167},
isbn = {978-1-4244-9563-4},
issn = {15223965},
journal = {2011 IEEE International Symposium on Antennas and Propagation (APSURSI)},
month = {7},
pages = {3025-3028},
publisher = {IEEE},
title = {Corrugations for suppressing undesired wave propagation in the transverse direction in a 45° linearly polarized 76 GHz parallel-plate waveguide two-dimensional slot-array},
url = {http://ieeexplore.ieee.org/document/5997167/},
year = {2011},
}
@article{Nikfal2011,
abstract = {A novel increased group-delay slope loop scheme is proposed to enhance the time-frequency resolution of dispersive delay structure (DDS) components for microwave analog signal processing systems. In this scheme, the signal at the output of the DDS is regenerated by an amplifier and reinjected via a nondispersive delay line toward its input along a loop. At each pass across the DDS, the effective group-delay slope of the system is increased so that, after n turns along the loop, the time-frequency resolution has been enhanced by a factor n. This approach provides a solution to the unpractical approach of cascading n DDS units, which would lead to excessively large device footprint, unacceptably high insertion loss, and severe signal-to-noise reduction. The proposed scheme is implemented in a proof-of-concept circuit using a C-section all-pass network DDS and demonstrated experimentally in a frequency meter and in a frequency discriminator. Possible improvements for higher performance are discussed. © 2006 IEEE.},
author = {B Nikfal and S Gupta and C Caloz},
doi = {10.1109/TMTT.2011.2117436},
issn = {0018-9480},
issue = {6},
journal = {IEEE Transactions on Microwave Theory and Techniques},
keywords = {All-pass networks,analog signal processing,dispersion engineering,group-delay engineering,increased group-delay slope loop,real-time analysis},
month = {6},
pages = {1622-1628},
title = {Increased Group-Delay Slope Loop System for Enhanced-Resolution Analog Signal Processing},
volume = {59},
url = {http://ieeexplore.ieee.org/document/5739133/},
year = {2011},
}
@inproceedings{Gupta2010,
abstract = {The concept of pulse-position modulation coding based on group delay engineered non-commensurate microwave C-section all-pass networks is introduced and demonstrated by simulation as novel RFID system. The proposed concept offers system simplicity, frequency scalability, high power efficiency and M-ary coding capability for large ID coding diversity. © 2010 IEICE Institute of Electronics Informati.},
author = {S. Gupta and B. Nikfal and C. Caloz},
isbn = {9784902339222},
journal = {Asia-Pacific Microwave Conference Proceedings, APMC},
keywords = {RFID,all-pass filters,group delay engineering,non-commensurate networks,pulse-position modulation},
title = {RFID system based on pulse-position modulation using group delay engineered microwave C-sections},
year = {2010},
}
@inproceedings{Gupta2010,
abstract = {The characterization and measurement of ultra-fast signals have become increasingly important with the emergence of ultra-wide band systems. In this context, real-time systems are required to effectively analyze and manipulate signal spectra in many microwave and millimeter-wave applications. In optics, the real-time Fourier transform is a well-known concept, where the spectrum of the signal is measured in the time domain from propagation in a first-order dispersive medium [1]. This principle has been recently applied to microwave signals using a reflective-type dispersive structures [2]. This paper presents an analog real-time Fourier transforming system based on transmission-type group delay engineered all-pass structures. In this system, the limitation on the time duration of the measurable signal is significantly relaxed as a result of the chirp inversion technique being employed. © 2010 IEEE.},
author = {S Gupta and C Caloz},
doi = {10.1109/APS.2010.5561143},
isbn = {978-1-4244-4967-5},
journal = {2010 IEEE Antennas and Propagation Society International Symposium},
month = {7},
pages = {1-4},
publisher = {IEEE},
title = {Analog real-time Fourier transformer using a group delay engineered C-section all-pass network},
url = {http://ieeexplore.ieee.org/document/5561143/},
year = {2010},
}
@article{,
abstract = {A numerical method is proposed for the analysis of highly dispersive linear and non-linear metamaterial structures. Firstly, pulse propagation along non-linear composite right/left-handed (CRLH) transmission line (TL) is studied. The dispersive CRLH line is loaded with hyper-abrupt diodes to achieve non-linearity. The characteristic impedance and propagation constant of each unit-cell of the CRLH TL is varied at each time-step, and the non-uniform line is then analysed. A novel interpolation scheme, based on the smooth behaviour of the propagation constant with small variations of the shunt capacitor is proposed. Numerical results show that high accuracy and up to 80% reduction of the computational cost is achieved. A general example which combines dispersion and non-linearity is presented, validated and discussed. Secondly, the impulse-regime radiation of a leaky-wave antenna is analysed and used to describe a real-time spectrogram analyser (RTSA). A new calibration method for the system, which takes into account the directivity variation of the antenna with frequency, is proposed. This method provides an extremely fast and accurate tool to characterise the behaviour of leaky-wave-based RTSA systems. © 2010 The Institution of Engineering and Technology.},
author = {J.S. Gómez-Díaz and S. Gupta and A. Álvarez-Melcón and C. Caloz},
doi = {10.1049/iet-map.2009.0205},
issn = {17518725},
issue = {10},
journal = {IET Microwaves, Antennas & Propagation},
pages = {1617},
title = {Efficient time-domain analysis of highly dispersive linear and non-linear metamaterial waveguide and antenna structures operated in the impulse-regime},
volume = {4},
url = {https://digital-library.theiet.org/content/journals/10.1049/iet-map.2009.0205},
year = {2010},
}
@article{Gupta2010,
abstract = {A group-delay engineered noncommensurate transmission line two-port all-pass network for analog signal-processing applications is presented, analytically modeled, and experimentally demonstrated. This network consists of transversally cascaded C-sections, which are distributed implementations of the bridged-T equalizer lumped circuit. It is obtained by interconnecting the alternate ports of adjacent lines of a 2N-port coupled transmission line network with transmission line sections, and it is modeled using multiconductor transmission line theory with per-unit-length capacitance matrix C and inductance matrix L. By allowing the different C-sections of the network to exhibit different lengths, a generalized group-delay engineering procedure is proposed, where quasi-arbitrary group-delay responses are achieved by combining the group-delay responses of C-sections with different lengths. A computer design approach based on genetic algorithms is applied for synthesis, which consists of determining the structural parameters of the different C-section groups. Using this approach, noncommensurate networks are group-delay engineered in edge-coupled stripline technology, and Gaussian, linear and quadratic group-delay responses are realized. The theoretical results are validated by experiment. Finally, two application examples of analog signal processinga tunable impulse delay line and a real-time frequency discriminatorusing the proposed dispersive noncommensurate all-pass networks are presented. © 2010 IEEE.},
author = {Shulabh Gupta and Armin Parsa and Etienne Perret and Richard V. Snyder and Robert J. Wenzel and Christophe Caloz},
doi = {10.1109/TMTT.2010.2058933},
issn = {0018-9480},
issue = {9},
journal = {IEEE Transactions on Microwave Theory and Techniques},
keywords = {All-pass circuits,analog signal processing,dispersive media,genetic algorithms (GAs),group-delay engineering,multiconductor transmission lines,noncommensurate networks},
month = {9},
pages = {2392-2407},
title = {Group-Delay Engineered Noncommensurate Transmission Line All-Pass Network for Analog Signal Processing},
volume = {58},
url = {http://ieeexplore.ieee.org/document/5549964/},
year = {2010},
}
@inproceedings{Gupta2010,
abstract = {A generalized group delay engineered C-section all-pass network is proposed and applied to a novel analog inverse Fourier transformer. This system map the time-domain waveform of broadband signals onto the frequency domain, using a linear time-to-frequency mapping. The system is analyzed and demonstrated for different testing signals. © 2010 EuMA.},
author = {S. Gupta and C. Caloz},
isbn = {9782874870163},
journal = {European Microwave Week 2010, EuMW2010: Connecting the World, Conference Proceedings - European Microwave Conference, EuMC 2010},
title = {Analog inverse Fourier transformer using group delay engineered C-section all-pass network},
year = {2010},
}
@article{,
abstract = {A novel tunable microwave broadband resonator, inspired from optical laser systems, is presented. In contrast to usual harmonic resonators, the proposed device is based on broadband composite right/left handed metamaterial lines. This line, configured as a resonator, provides nonuniform spectral resonances due to the nonlinear nature of its dispersion curve. This is exploited in the impulse regime, where the input pulse spectrum is discretized inside the resonator, with different spectral separation as a function of the carrier frequency. This discretization leads to a pulse periodicity in time, with a tunable output time period. On the basis of the new broadband resonator features, a pulse rate multiplication device is proposed. This device provides an increase in the repetition rate of a periodic input pulse, with the additional advantage of repetition rate tunability. Copyright 2009 by the American Geophysical Union.},
author = {J. S. Gómez-Díaz and A. Alvarez-Melcon and S. Gupta and C. Caloz},
doi = {10.1029/2008RS003991},
issn = {00486604},
issue = {4},
journal = {Radio Science},
month = {8},
pages = {n/a-n/a},
title = {Impulse regime CRLH resonator for tunable pulse rate multiplication},
volume = {44},
url = {http://doi.wiley.com/10.1029/2008RS003991},
year = {2009},
}
@inproceedings{Gupta2009,
abstract = {An analog frequency resolved electrical gating (FREG) system based on a composite right/left-handed (CRLH) leaky-wave antennas for UWB signal characterization is proposed. This system is based on spatial-spectral decomposition property of the leaky-wave antenna and on the self-gating principle to suppress the time-frequency resolution dependence on the antenna physical length in the spectrograms. The system is demonstrated numerically using an efficient time-domain Green's function technique and spectrograms are shown for various time domain test signals. © 2009 EuMA.},
author = {S. Gupta and J.S. Gómez-Díaz and C. Caloz},
doi = {10.1109/EUMC.2009.5296244},
isbn = {9782874870118},
journal = {European Microwave Week 2009, EuMW 2009: Science, Progress and Quality at Radiofrequencies, Conference Proceedings - 39th European Microwave Conference, EuMC 2009},
title = {Frequency resolved electrical gating (FREG) system based on a CRLH leaky-wave antenna for UWB signal characterization},
year = {2009},
}
@article{,
abstract = {The phenomenology of impulse-regime propagation along metamaterial composite right/left-handed transmission lines (CRLH TL) is examined. For this purpose, a closed-form time-domain Green's function approach, based on the inverse Fourier transform of the 1D transmission line model, is applied. Since the CRLH TLs are electrically thin, this model is adequate to describe transient phenomena. The method is validated experimentally for the case of matched and mismatched CRLH impulse delay lines. Excellent agreement between theory and experiments is obtained. Various complex dispersive phenomena are investigated, including pulse delay as a function of the modulation frequency, pulse compression, and temporal Talbot pulse rate multiplication. © 2009 IEEE.},
author = {J.S. Gomez-Diaz and S. Gupta and A. Alvarez-Melcon and C. Caloz},
doi = {10.1109/TAP.2009.2025400},
issn = {0018-926X},
issue = {12},
journal = {IEEE Transactions on Antennas and Propagation},
keywords = {Composite right/left-handed (CRLH) metamaterials,Green functions,Time-domain analysis,Transmission line theory},
month = {12},
pages = {4010-4014},
title = {Investigation on the Phenomenology of Impulse-Regime Metamaterial Transmission Lines},
volume = {57},
url = {http://ieeexplore.ieee.org/document/5075643/},
year = {2009},
}
@inproceedings{,
abstract = {This paper examines pulse propagation along linear and non linear composite right/left handed transmission lines (CRLH TLs). An analytical time-domain Green's functions approach is employed in the linear case. Pulse spreading in time, due to the dispersive features of the line, and tunable pulse group velocity are demonstrated and validated using Agilent ADS. The formulation is further extended to analyze non-linear CRLH TLs (loaded with shunt varactors), using an iterative scheme. This type of lines combines dispersion and nonlinearity phenomena, which may provide optical-inspired applications at microwaves. A microstrip prototype of a nonlinear CRLH TL has been fabricated and tested, and a unit-cell circuital model is proposed. The variation of the varactor's DC bias is employed to electrically control the band-gap which occurs at the CRLH transition frequency. Finally, harmonic generation is experimentally demonstrated showing good agreement with the proposed theory. © 2009 IEEE.},
author = {J. S. Gomez-Diaz and S. Gupta and A. Alvarez-Melcon and C. Caloz},
doi = {10.1109/ICEAA.2009.5297440},
isbn = {978-1-4244-3385-8},
journal = {2009 International Conference on Electromagnetics in Advanced Applications},
month = {9},
pages = {280-283},
publisher = {IEEE},
title = {Numerical analysis of impulse regime phenomena in linear and non-linear metamaterial transmission lines},
url = {https://ieeexplore.ieee.org/document/5297440/},
year = {2009},
}
@article{,
abstract = {A tunable spatio-temporal Talbot imaging phenomenon is presented. This phenomenon is based on the radiation properties of an array of beam-steered metamaterial composite right-/left-handed leaky-wave antennas, which is excited by a modulated pulse. The scanning law property of these antennas is exploited to achieve off-axis radiation, which leads to a tunable Talbot distance, as a function of the input pulse modulation frequency. The proposed Talbot phenomenon is analyzed theoretically, taking into account the aberrations produced by higher-order terms present in the free-space transfer function. Numerical simulations confirm the self-imaging and pulse multiplication effects and their tunability capabilities as a function of frequency. Finally, the experimental results are included to confirm the phenomenon predicted. © 2009 American Institute of Physics.},
author = {J. S. Gómez-Díaz and A. Álvarez-Melcón and S. Gupta and C. Caloz},
doi = {10.1063/1.3213382},
issn = {0021-8979},
issue = {8},
journal = {Journal of Applied Physics},
month = {10},
pages = {084908},
title = {Tunable Talbot imaging distance using an array of beam-steered metamaterial leaky-wave antennas},
volume = {106},
url = {http://aip.scitation.org/doi/10.1063/1.3213382},
year = {2009},
}
@inproceedings{,
abstract = {A spatial-temporal Talbot phenomenon, based on metamaterial composite right/left-handed (CRLH) leaky-wave antennas (LWAs), is presented. The phenomenon is based on the combination of the regular spatial Talbot effect and the transient character of the pulse radiation phenomenon in the LWA structure, and it is localized both in space in time. The CRLH LWA scanning properties are used to obtain, for the first time in the microwave domain, a tunable Talbot effect as a function of frequency. A novel mathematical development is proposed to the analysis of the impulse-regime radiation of the CRLH LWA array. The presented Talbot phenomenon is analyzed theoretically and validated numerically for the case of narrowband pulses.},
author = {J.S. Gomez-Daz and S. Gupta and A.A. Melcon and C. Caloz},
isbn = {9783000245732},
journal = {European Conference on Antennas and Propagation, EuCAP 2009, Proceedings},
title = {Spatial-temporal talbot effects in impulse-regime metamaterial leaky-wave antennas},
year = {2009},
}
@article{Gupta2009,
abstract = {Several novel dispersion-engineered CRLH TL metamaterial analog signal processing systems, exploiting the broadband dispersive characteristics and design flexibility of CRLH TLs, are presented. These systems are either guided-wave or radiated-wave systems, and employ either the group velocity or the group velocity dispersion parameters. The systems presented are: a frequency tunable impulse delay line, a pulse-position modulator, a frequency discriminator and real-time Fourier transformer, pulse generators, an analog real-time spectrum analyzer, a frequencyresolved electrical gating, a spatio-temporal Talbot effect imager, and analog true-time delayer. They represent a new class of impulse-regime metamaterial structures, while previously reported metamaterials were mostly restricted to the harmonic regime.},
author = {S. Gupta and C. Caloz},
issn = {12102512},
issue = {2},
journal = {Radioengineering},
keywords = {Analog signal processing,Dispersion engineering,Leaky-wave antennas,Pulseposition modulators,Real-time Fourier transformation,Real-time spectrum analyzers,Talbot effect,Transmission line metamaterials,True-time delayers},
title = {Analog signal processing in transmission line metamaterial structures},
volume = {18},
year = {2009},
}
@inproceedings{Gupta2009,
abstract = {A frequency division full-diplexing transceiver system is proposed based on the beam-scanning property of the composite right/left-handed (CRLH) leaky-wave antenna (LWA). A full-diplexing operation of simultaneous transmission and receiving is experimentally demonstrated. Compared to the conventional systems, the proposed system operates with a single passive CRLH antenna resulting in lesser hardware requirements and provides high signal isolation due to the directive nature of the leaky-wave antenna and the band-pass filter employed in the system. ©2009 IEEE.},
author = {Shulabh Gupta and Hoang V. Nguyen and Toshiro Kodera and Samer Abielmona and Christophe Caloz},
doi = {10.1109/APMC.2009.5385300},
isbn = {978-1-4244-2801-4},
journal = {2009 Asia Pacific Microwave Conference},
keywords = {Composite right/left-handed transmission lines,Frequency diplexer,Leaky-wave antennas},
month = {12},
pages = {2014-2017},
publisher = {IEEE},
title = {CRLH leaky-wave antenna based frequency division diplexing transceiver yes},
url = {http://ieeexplore.ieee.org/document/5385300/},
year = {2009},
}
@article{Gupta2009,
abstract = {A novel analog real-time spectrum analyzer (RTSA) for the analysis of complex nonstationary signals (such as radar, security and instrumentation, and electromagnetic interference/ compatibility signals) is presented, demonstrated, and characterized. This RTSA exploits the space-frequency mapping (spectral-spatial decomposition) property of the composite right/left-handed (CRLH) leaky-wave antenna (LWA) to generate the real-time spectrograms of arbitrary testing signals. Compared to digital RTSAs, it exhibits the advantages of instantaneous acquisition, low computational cost, frequency scalability, and broadband or ultra-wideband operation. The system is demonstrated both theoretically by a commercial full-wave simulator and an efficient Green's function approach and experimentally by a parallel-waveguide prototype including a metal-insulator-metal CRLH LWA, 16 patch antenna probe detectors circularly arranged around the LWA, and a digital oscilloscope performing analog/digital conversion and time-domain acquisition before the postprocessing and displaying of the spectrogram. The system is tested for a large diversity of nonstationary signals and generates, in all cases, spectrograms that are in excellent agreement with theoretical predictions. The fundamental tradeoff between time and frequency resolutions inherent to all RTSA systems is also discussed, and an interchangeable multi-CRLH LWA solution is proposed to handle signals with different time durations. © 2009 IEEE.},
author = {S. Gupta and S. Abielmona and C. Caloz},
doi = {10.1109/TMTT.2009.2034223},
issn = {0018-9480},
issue = {12},
journal = {IEEE Transactions on Microwave Theory and Techniques},
keywords = {Composite right/left-handed (CRLH),Joint time-frequency representation,Leaky-wave antenna (LWA),Metamaterials,Real-time spectrum analyzer (RTSA),Short-time Fourier transform (STFT),Spectrogram,Time-domain Green's functions},
month = {12},
pages = {2989-2999},
title = {Microwave Analog Real-Time Spectrum Analyzer (RTSA) Based on the Spectral–Spatial Decomposition Property of Leaky-Wave Structures},
volume = {57},
url = {http://ieeexplore.ieee.org/document/5299041/},
year = {2009},
}
@article{Abielmona2009,
abstract = {A compressive receiver (CR) is presented utilizing a composite right/left-handed (CRLH) dispersive delay line (DDL) for analog signal processing applications. The CRLH DDL offers advantages such as arbitrary frequency of operation and wide bandwidth, filling a gap with competing DDL technologies. The presented CR system utilizes an impulse-driven CRLH DDL and mixer inversion for chirp generation required for real-time signal processing. At high frequencies, this eliminates frequency ramp generators. The CR is employed as a frequency discriminator and a tunable delay line with dispersion compensation. The simulation and experimental results fully validate the presented systems as proof-of-concept for high-frequency applications such as real-time Fourier transformers and signal analyzers. © 2009 IEEE.},
author = {S. Abielmona and S. Gupta and C. Caloz},
doi = {10.1109/TMTT.2009.2031927},
issn = {0018-9480},
issue = {11},
journal = {IEEE Transactions on Microwave Theory and Techniques},
keywords = {Analog signal processing,Composite right/lefthanded (CRLH),Compressive receiver (CR),Metamaterials,Real-time Fourier transformer},
month = {11},
pages = {2617-2626},
title = {Compressive Receiver Using a CRLH-Based Dispersive Delay Line for Analog Signal Processing},
volume = {57},
url = {http://ieeexplore.ieee.org/document/5272478/},
year = {2009},
}
@inproceedings{Gupta2008,
abstract = {A novel real-time spectrum analyzer (RTSA) is presented. This RTSA exploits the frequency-space mapping property of the composite right/left handed (CRLH) leaky-wave structure to generate spectrograms with unrestricted time-frequency resolution, not available in current competing systems. Moreover, it exhibits the advantages of low computational burden, frequency scalability and broadband (UWB) operation. The system is demonstrated by both full-wave analysis and experiments for various test signals. © 2008 IEEE.},
author = {S. Gupta and C. Caloz and S. Abielmona},
doi = {10.1109/MWSYM.2008.4632955},
isbn = {978-1-4244-1780-3},
issn = {0149645X},
journal = {2008 IEEE MTT-S International Microwave Symposium Digest},
keywords = {Leaky-wave antennas,RTSA,Real-time systems,Short-time Fourier transform,Spectrogram,Time-frequency analysis},
month = {6},
pages = {807-810},
publisher = {IEEE},
title = {CRLH leaky-wave real-time spectrum analyzer (RTSA) with unrestricted time-frequency resolution},
url = {http://ieeexplore.ieee.org/document/4632955/},
year = {2008},
}
@article{,
abstract = {A spatialoral Talbot phenomenon, based on metamaterial composite right/left-handed (CRLH) leaky-wave antennas (LWAs), is presented. This phenomenon, reported in the microwave domain, is based on the combination of the conventional spatial monochromatic Talbot effect and the transient (polychromatic) character of the pulse radiation phenomenon in the LWA structure. When the elements of a periodic CRLH LWA array are fed simultaneously by an input pulse, the spatial beams corresponding to different temporal frequencies constructively interfere in space so as to form a self-imaged pattern constituted by narrow Talbot zones. This Talbot effect is spatialoral since the Talbot zones are localized both in space and time. The phenomenon is analyzed theoretically and validated numerically for the case of narrow-band pulses. © 2008 American Institute of Physics.},
author = {J. S. Gómez-Díaz and A. Alvarez-Melcon and S. Gupta and C. Caloz},
doi = {10.1063/1.3013905},
issn = {0021-8979},
issue = {10},
journal = {Journal of Applied Physics},
month = {11},
pages = {104901},
title = {Spatio-temporal Talbot phenomenon using metamaterial composite right/left-handed leaky-wave antennas},
volume = {104},
url = {http://aip.scitation.org/doi/10.1063/1.3013905},
year = {2008},
}
@article{Shahvarpour2008,
abstract = {The existence of solitons in SiO2 -Ag- SiO2 and Ag- SiO2 -Ag plasmonic waveguides (PWGs) is investigated using a nonlinear transmission line approach. Both the SiO2 -Ag- SiO 2 and the Ag- SiO2 -Ag, the former in its TM even mode and the latter in its odd mode, are shown to support bright solitons as solutions to the nonlinear Schrödinger equation. The SiO2 -Ag- SiO 2 even mode has low left-handed (LH) loss but is undesirably mixed with a right-handed mode, while the Ag- SiO2 -Ag odd mode exhibits low-loss pure LH characteristics and is therefore the most suited mode for soliton propagation. Soliton PWGs may find applications in compact switching, pulse shaping, and pulse compressing devices. © 2008 American Institute of Physics.},
author = {Attieh Shahvarpour and Shulabh Gupta and Christophe Caloz},
doi = {10.1063/1.3048548},
issn = {0021-8979},
issue = {12},
journal = {Journal of Applied Physics},
month = {12},
pages = {124510},
title = {Schrödinger solitons in left-handed SiO2–Ag–SiO2 and Ag–SiO2–Ag plasmonic waveguides calculated with a nonlinear transmission line approach},
volume = {104},
url = {http://aip.scitation.org/doi/10.1063/1.3048548},
year = {2008},
}
@inproceedings{Rennings2007,
abstract = {A novel power splitter based on coupled surface plasmons (SPs) is proposed for optical frequency applications. This power divider is an ultra-compact forward or co-directional coupling device. A specific SiO2-Ag- SiO2 685-THz design is demonstrated by full-wave analysis, where a coupling length of only 36 nm and an overall dimension of around 500 nm is achieved. The underlying principle of coupled SPs may lead to various novel nanoscale optical devices. © 2007 IEEE.},
author = {A. Rennings and J. Mosig and S. Gupta and C. Caloz and R. Kashyap and D. Erni and P. Waldow},
doi = {10.1109/ISSSE.2007.4294515},
isbn = {1-4244-1448-2},
journal = {2007 International Symposium on Signals, Systems and Electronics},
keywords = {Co-directional coupler,Integrated optics,Nanoscale optical device,Power splitter,Surface plasmons},
month = {7},
pages = {471-474},
publisher = {IEEE},
title = {Ultra-Compact Power Splitter Based on Coupled Surface Plasmons},
url = {http://ieeexplore.ieee.org/document/4294515/},
year = {2007},
}
@article{Abielmona2007,
abstract = {A new tunable delay system is presented and demonstrated experimentally in this letter. This system, which incorporates a composite right/left-handed (CRLH) transmission line, two mixers, and a low-pass filter, achieves a tunable group delay for impulse and continuous-wave signals, controlled by a local oscillator. This group delay tunability follows from the dispersion property of the CRLH transmission line and is achieved without suffering from the drawbacks of conventional delay lines in terms of matching, frequency of operation, and planar circuit implementation. The realized prototype exhibits measured group delays tunable between 5.1 and 8.54 ns over a frequency range of 2-4.5 GHz. © 2007 IEEE.},
author = {Samer Abielmona and Shulabh Gupta and Christophe Caloz},
doi = {10.1109/LMWC.2007.910492},
issn = {1531-1309},
issue = {12},
journal = {IEEE Microwave and Wireless Components Letters},
keywords = {Composite right/left-handed (CRLH),Continuous wave (CW),Delay line,Group delay,Impulse,Tunable},
month = {12},
pages = {864-866},
title = {Experimental Demonstration and Characterization of a Tunable CRLH Delay Line System for Impulse/Continuous Wave},
volume = {17},
url = {http://ieeexplore.ieee.org/document/4385730/},
year = {2007},
}
@inproceedings{Gupta2007,
author = {Shulabh Gupta and Samer Abielmona and Christophe Caloz},
doi = {10.1109/APS.2007.4396799},
isbn = {978-1-4244-0877-1},
issn = {15223965},
journal = {2007 IEEE Antennas and Propagation Society International Symposium},
month = {6},
pages = {5523-5526},
publisher = {IEEE},
title = {Carrier frequency tunable impulse/continuous wave CRLH delay line system},
url = {https://ieeexplore.ieee.org/document/4396799/},
year = {2007},
}
@inproceedings{Gupta2007,
abstract = {The existence of a solitary wave and soliton solutions in a nonlinear (NL) left-handed (LH) transmission line (TL) loaded with nonlinear varactor diodes is demonstrated rigorously for the first time and corresponding closed-form solutions are provided. These solutions are modulated dark and a bright solitons for the cases of heterostructure barrier varactor (HBV) and hypcrabrupt junctions varactor (HJV) diodes, respectively. It is shown that NL LH TLs, despite their very different dispersion response, may support solitons identical to those in optical fibers in their normal dispersion regime, in contrast to RH TLs which can support only non-modulated (KdV) and bright solitons. Due to this equivalence, It. maybe be anticipated that NL LH TLs will lead to several novel and unique microwave applications, such as UWB pulse shapers and compressors, which will be developed by transposition of concepts from lhe photonics. © 2007 IEEE.},
author = {Shulabh Gupta and Christophe Caloz},
doi = {10.1109/MWSYM.2007.380183},
isbn = {1-4244-0687-0},
issn = {0149-645X},
journal = {2007 IEEE/MTT-S International Microwave Symposium},
keywords = {Metamaterials,Nonlinear (NL) Transmission lines (TLs),Solitary waves,Solitons,Varactor diodes},
month = {6},
pages = {979-982},
publisher = {IEEE},
title = {Dark and Bright Solitons in Left-Handed Nonlinear Transmission Line Metamaterials},
url = {http://ieeexplore.ieee.org/document/4263989/},
year = {2007},
}
@inproceedings{Gupta2006,
abstract = {In this work, the problem of propagation of ultrashort optical solitons through a non-linear optical fiber is investigated in the joint Time-Frequency (TF) domain using optimized representations [i.e. Wigner-Ville (WV) Distribution or WV-Spectrograms with reduced cross-term interferences]. Based on these optimized representations, complete numerical simulations for nonlinear propagation of solitons were carried out. In particular we have analyzed the evolution of second and third order solitons and soliton interaction in optical fibers using joint TF representations.},
author = {S. Gupta and J. Azaña},
doi = {10.1117/12.707708},
editor = {Pierre Mathieu},
isbn = {0819464287},
issn = {0277786X},
journal = {Proceedings of SPIE - The International Society for Optical Engineering},
keywords = {Nonlinear pulse propagation,Solitons,Spectrograms,Wigner-ville distribution},
month = {9},
pages = {63430V},
title = {Joint time-frequency analysis of ultrashort soliton propagation in nonlinear optical fibers},
volume = {6343 I},
url = {http://proceedings.spiedigitallibrary.org/proceeding.aspx?doi=10.1117/12.707708},
year = {2006},
}
@article{,
abstract = {We introduce a new family of equivalent periodic phase-only filtering configurations that can be used for implementing the Talbot-based pulse rate multiplication technique. The introduced family of periodic Talbot filters allows one to design a desired pulse repetition rate multiplier with an unprecedented degree of freedom and flexibility. Moreover, these filters can be implemented using all-fiber technologies, and in particular (superimposed) linearly chirped fiber Bragg gratings. The design specifications and associated constraints of this new class of Talbot filters are discussed. © 2006 Optical Society of America.},
author = {José Azaña and Shulabh Gupta},
doi = {10.1364/OE.14.004270},
issn = {1094-4087},
issue = {10},
journal = {Optics Express},
pages = {4270},
title = {Complete family of periodic Talbot filters for pulse repetition rate multiplication},
volume = {14},
url = {https://opg.optica.org/oe/abstract.cfm?uri=oe-14-10-4270},
year = {2006},
}
@inproceedings{Gupta2005,
abstract = {The problem of propagation of a periodic optical pulse sequence through a linear dispersive fiber is investigated in the joint time-frequency domain. This study provides a new and deeper insight into the dynamics of formation of the integer and fractional temporal Talbot patterns which are observed along the fiber propagation distance. © 2005 IEEE.},
author = {S. Gupta and P.F. Ndione and J. Azana and R. Morandotti},
doi = {10.1109/LEOSST.2005.1528044},
isbn = {0-7803-8981-6},
issn = {10994742},
journal = {Digest of the LEOS Summer Topical Meetings, 2005.},
pages = {163-164},
publisher = {IEEE},
title = {Time-frequency analysis of temporal talbot effect},
volume = {2005},
url = {http://ieeexplore.ieee.org/document/1528044/},
year = {2005},
}
@inproceedings{Gupta2005,
abstract = {Temporal Talbot effect is the time domain counterpart of spatial self imaging phenomenon. When a periodic time signal is propagated through a first order dispersive medium, exact replicas of the signal are reproduced at specific distance along the direction of propagation. At other distances, the signal is self imaged with a higher repetition-rate than the original periodic sequence (Fractional Talbot effect). In this paper, the problem of propagation of an ideal periodic optical pulse sequence through a linear dispersive fiber is investigated in the joint time-frequency domain using an optimized representation [i.e. Wigner Ville-Multiresolution spectrograms providing an optimal resolution in both time and frequency domains with reduced cross-term interferences]. Based on these optimized representations, complete numerical simulations were carried out to analyze the evolution of the time-frequency distribution of a periodic signal propagating through a linear dispersive medium, thus providing a deeper insight into the physics of the temporal Talbot problem. Moreover, we have used an elegant ray-matrix approach to describe the signal propagation in phase space and we have showed that for the fractional temporal Talbot effect (repetition rate factor M), each newly generated individual temporal pulse has contributions only from every Mth spectral component of the train's discrete spectrum. This interpretation is in fact in very good agreement with the notion that the fractional temporal Talbot effect can be explained as a result of interference between consecutive, chirped TF patterns. Our numerical simulations have confirmed our heuristic descriptions of the Talbot phenomena.},
author = {S. Gupta and P.F. Ndione and J. Azaña and R. Morandotti},
doi = {10.1117/12.629288},
issn = {0277786X},
journal = {Proceedings of SPIE - The International Society for Optical Engineering},
keywords = {Pulse propagation in linear dispersive medium,Spectrograms,Temporal Talbot Effect,Time-Frequency Analysis,Wigner-Ville},
title = {A new insight into the problem of temporal Talbot phenomena in optical fibers},
volume = {5971},
year = {2005},
}
