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Application of metasurfaces in the design of performance-enhanced low-profile antennas
摘要： This paper presents a review of metasurface-based antennas conducted at the Microwave Communication Laboratory (MCL) of Ajou University in the Republic of Korea. In this paper, pro?le miniaturization, bandwidth enhancement, multiband operation, and radiation pattern control of metasurface-based antennas are considered. The paper ?rst presents metasurface-based antennas implemented by placing various radiators on top of the metasurface. It then presents antennas implemented by placing the radiators below the metasurface with and without the ground plane. Metasurface-based antennas are not only able to achieve high ef?ciency with a low pro?le but they are also able to generate extra resonances from the metasurface structures, which signi?cantly enhances the overall performance of the antennas. These additional resonances were utilized in multiband and/or wideband operations. In addition, the design of a planar compact wide-gain-bandwidth metasurface-based antenna and its radiation characteristics are presented at a terahertz (THz) frequency range. The THz antennas were designed with metasurfaces and a planar leaky-wave feeding structure. Finally, the outlook on future research at the MCL for antenna-related work and their applications using metasurfaces is provided.
关键词： surface wave resonance,sequential rotation,crossed dipole,arti?cial magnetic conductor,metamaterial,wideband,circular polarization,leaky-wave,Antenna,array,metasurface
更新于2025-09-23 15:23:52
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Single-Layer Multi-Via Loaded CRLH Leaky-Wave Antennas for Wide-Angle Beam Scanning with Consistent Gain
摘要： Achieving continuous backward-to-forward wide-angle beam scanning with consistent gain by employing composite right/left-handed leaky-wave antennas (LWAs) is reported. For structural and design simplicity, a single-layer 1-D structure is considered in which each unit cell consists of a patch shorted centrally to the ground plane. It was found that, when using only one via at the center of a unit cell, a continuous beam scan requires a large diameter via when all other parameters remain unchanged. To eliminate this limitation while maintaining a single-layer structure, novel unit cells are proposed using multiple vias in each unit cell. An LWA design for continuous beam scan with three vias in each unit cell is investigated and the results show good performance and design flexibility. A prototype antenna has been realized, and the measured results show that the antenna can scan the radiation beam continuously in a wide range, from ?60° to +66° with a consistent gain. The measured gain variation within the scan range is only 2.9 dB, and the 3dB gain bandwidth is 58.6%.
关键词： single-layer,leaky-wave antenna (LWA),backward and forward,consistent gain,composite right/left-handed (CRLH),Beam scanning
更新于2025-09-23 15:23:52
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Nonreciprocal optical links based on time-modulated nanoantenna arrays: Full-duplex communication
摘要： Interference of transmitted and received signals hinders the simultaneous functionality of a conventional optical antenna as a transmitter and receiver which is required for full-duplex communication. The full-duplex communication schemes enabled by dense wavelength division multiplexed optical networks require distinct transmitter/receiver components operating at different wavelengths which increase the cost, complexity, and footprint of the physical layer. In this work, we demonstrate that an array of nanoantennas with leaky-wave architecture based on spatiotemporal modulation establishes nonreciprocal optical links which can reject the interference of transmitted and received signals by isolating the frequency of transmission and reception modes. For this purpose, we integrate indium-tin oxide into plasmonic nanodipoles which allows for realization of time-modulated nanoantennas in near-infrared frequency regime through electrical modulation of charge carrier density with radio-frequency signals. The radiation characteristics of individual nanoantennas and modal properties of nanoantenna arrays are rigorously studied through linking of charge transport and electromagnetic models. To this end, we extend the formulation of discrete dipole approximation as the standard modeling tool for electromagnetic scattering from nanoantenna arrays to treat realistic time-modulated structures with drastically different timescales between optical and modulation frequencies. The operation of spatiotemporally modulated array antennas in transmission and reception modes is investigated. Moreover, electrical beam-scanning functionality and dependence of antenna characteristics to modulation parameters and wavelength are demonstrated. It is rigorously established that such array antennas can operate as full transceivers by separating the transmitted and received signals propagating along the same direction through down conversion and up conversion of the frequency. Our results provide a route toward realization of optical antenna systems capable of full-duplex communication and real-time beam scanning which can increase the capacity and decrease the complexity of optical networks.
关键词： nonreciprocal optical links,indium-tin oxide,leaky-wave antenna,discrete dipole approximation,full-duplex communication,time-modulated nanoantenna arrays,spatiotemporal modulation
更新于2025-09-23 15:23:52
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[IEEE 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Chengdu, China (2018.5.7-2018.5.11)] 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Wide-Angle Frequent Scanning Metamaterial Leaky Wave Antenna Array for Automotive Radars
摘要： This paper designs a wide-angle frequency scanning metamaterial (MTM) leaky wave antenna (LWA) array for automotive radars. The gap capacitors and the vialess open stub-loaded resonators are used to construct the frequency scanning MTM LWA array. The propagation constant of the MTM LWA array is able to change from negative to positive values as the frequency is increased, resulting in backward to forward beam scanning. Compared to mechanical beam scanning arrays and phased arrays, the frequency scanning MTM LWA arrays have advantages of reducing the system complexity, light weight and low cost. The presented MTM LWA array has a maximum gain of 13 dB and wide scanning angle from -60° to +80° as the frequency varies from 23.5 to 25.6 GHz which is well suited for automotive radar applications.
关键词： frequency scanning antenna,composite right/left-handed transmission line,Antenna array,metamaterial,leaky wave antenna
更新于2025-09-23 15:22:29
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Broadside Scanning Asymmetric SIW LWA with Consistent Gain and Reduced Side Lobe
摘要： In this paper, a backwards-to-forward continuous beam scanning leaky wave antenna (LWA) is presented in substrate integrated waveguide (SIW) technology. The antenna radiates from a continuous longitudinal slot etched on its broad wall. The slot is excited by using periodic H-plane steps. An impedance matched unit cell structure is used to suppress the open stop-band in the broadside direction. Bloch wave analysis is used to obtain the propagation characteristics of the antenna. However, due to radiation being obtained only from the shunt type radiating element viz., the longitudinal slot, a gain dip is observed in the broadside direction. Transversal asymmetry is then introduced in the structure to eliminate the gain dip and obtain consistent gain. A prototype of the antenna is fabricated and measured. Continuous beam scanning is achieved from –29o to +30o about the broadside direction with a gain variation of less than 2 dB over 8.0–12.4 GHz. A measured peak gain of 16.1 dBi is obtained. Key structural design parameters of the antenna are identified for controlling the leakage rate. Next, Taylor tapered aperture illumination is used to obtain low sidelobe level (SLL). The Taylor tapered antenna is also fabricated with the measured SLL below -21 dB.
关键词： substrate integrated waveguide (SIW),broadside radiation,Taylor distribution,Leaky-wave antenna (LWA)
更新于2025-09-23 15:21:21
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[IEEE 2019 IEEE Asia-Pacific Microwave Conference (APMC) - Singapore, Singapore (2019.12.10-2019.12.13)] 2019 IEEE Asia-Pacific Microwave Conference (APMC) - Conformal Leaky-Wave Antenna Based on Partially Filled Rectangular Waveguide
摘要： The present paper is devoted to the development of a conformal leaky-wave antenna based on a curved rectangular waveguide. The process of obtaining the required beam position is about longitudinal tailoring the phase velocity. This is achieved with choosing the thickness of dielectric, which partially fills the slotted waveguide. The difference between wavelengths in curved and straight waveguides is taken into account. An amplitude distribution function is realized by means of traditional adjusting the each particular slot parameters. The results of computer simulation validate the proposed design technique.
关键词： rectangular waveguide,dielectric filling,phase velocity,conformal antenna,leaky-wave antenna,beam forming
更新于2025-09-23 15:21:01
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45?° Linearly Polarized and Circularly Polarized High-Scanning-Rate Leaky-Wave Antennas Based on Slotted Substrate Integrated Waveguide
摘要： A class of 45? linearly polarized and circular polarized high scanning rate leaky wave antennas are proposed in this paper, which is based on slow-wave substrate integrated waveguide structure. High scanning rate leaky wave antennas have recently become attractive for imaging applications and automotive radar. These applications also require a continuous scanning range without an open stopband, as seen at broadside for ordinary leaky wave antennas. Furthermore, both 45? linearly polarization and circularly polarization are required in practical applications. In this paper, we propose an all-in-one leaky wave antenna design, which features high scanning rate, continuous scanning capability across the broadside, 45? linear polarization or circularly polarization, single-layer configuration, and single-side radiation. Two design examples are provided to illustrate the proposed principle. Both simulation and experimental validation are given.
关键词： open stopband,Leaky wave antenna,substrate integrated waveguide,circular polarization,scanning rate,linear polarization
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE International Symposium on Phased Array System & Technology (PAST) - Waltham, MA, USA (2019.10.15-2019.10.18)] 2019 IEEE International Symposium on Phased Array System & Technology (PAST) - Periodic Substrate Integrated Waveguide Based Leaky Wave Antenna for Backward Endfire Radiation
摘要： A new substrate integrated waveguide (SIW) based leaky wave antenna (LWA) is presented in this paper for backward endfire (-900) radiation. Measured gain at backward endfire is 12.1 dBi. To verify the simulated results, a prototype is fabricated. The proposed antenna is well suited for applications including unmanned aerial vehicles (UAVs), modern RADAR systems, directional communication systems, modern missiles and self-driving cars etc.
关键词： Endfire,Leaky Wave Antenna,Backfire,Broadside,Substrate Integrated Waveguide,Gain
更新于2025-09-23 15:19:57
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Electronically controlled beam steering leaky wave antenna in nematic liquid crystal technology
摘要： A novel nematic liquid crystal (LC) technology-based electronically controlled leaky wave antenna (LWA) with microstrip-waveguide conversion working mechanism and wide beam steering range is presented in this article. The LWA is a combination of an inverted microstrip structure and rectangular waveguide. According to the characteristics of LC materials in microwave band, a broadband microstrip-waveguide conversion device is proposed. The gradient slot leaky wave structure is combined with the microstrip-waveguide conversion device to form an electronically controlled LWA with continuous tunable beam. Simulation and experiment results show that the LWA proposed in this article has a 32° beam scanning range at 12 GHz and good impedance matching and stable gain, suggesting the great potential of nematic LC materials for extensive applications in microwave band in the future.
关键词： leaky wave antenna (LWA),microstrip-waveguide conversion,beam steering,nematic,liquid crystal (LC)
更新于2025-09-23 15:19:57
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Graphene-Based Composite Right/Left-Handed Leaky-Wave Antenna at Terahertz
摘要： In this paper, a simple terahertz (THz) leaky-wave antenna (LWA) composed of periodic gapped graphene ribbons and a silicon substrate is presented. The graphene sheets of the antenna operate in an electric field with a resonance distribution of transverse electric (TE) surface plasmon polaritons (SPPs). The THz LWA has both negative and positive propagation constant with the variation of frequencies. Thus, the LWA performs as a composite right/left-handed (CRLH) LWA with backfire-to-endfire beam steering capability in the THz band. The working principle of the THz LWA is analyzed in detail using the theory of dispersion relation formulae and the equivalent CRLH circuit model. The THz LWA is verified by numerical simulations, and the frequency scannable capability of the THz LWA is confirmed. The proposed antenna has great potential applications for the THz LWA of the radiation capability in the entire upper quadrants.
关键词： Composite right/left-handed,Terahertz,Beam-steering,Graphene,Leaky-wave antenna
更新于2025-09-23 15:19:57