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A Linear-to-Circular Polarization Conversion Metasurface Based Wideband Aperture Coupled Antenna
摘要： This paper proposes an aperture-coupled antenna with an ultrathin, single-layer metasurface for linear-to-circular (LP–CP) polarization conversion. The unit cell of the metasurface consists of a hexagonal ring surrounded by a square ring printed on both sides of a dielectric substrate for wideband LP-CP conversion. A patch antenna excited by an H-shaped slot aperture uses a 5 × 5 array of the metasurface as a superstrate. Simulated and measured radiation patterns of the proposed antenna are in good agreement. Measured S11 and axial ratio bandwidth of the proposed antenna are 21.5% and 19.23% respectively. Boresight radiation gain is around 10 dBic over 9.5 GHz to 11.5 GHz.
关键词： Circular polarization,Polarization conversion,Metasurface,Aperture coupled antenna,Wideband
更新于2025-09-23 15:19:57
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Circularly Polarized SIW DRA Fed by Ridge Gap Waveguide for 60??GHz Communications
摘要： A compact planar dielectric resonator antenna (DRA) is designed based on the sub-strate integrated waveguide (SIW) technology for 60? GHz communications. The pro-posed? antenna is constructed from a multilayered dielectric substrate separated by metallic sheets. A dog-bone shaped DRA is formed by perforating the upper dielectric sub-strate?with air holes surrounding the dog-bone structure. The DRA?is surrounded by metal-lic vies connecting two metal sheets above and below the substrate containing the?DRA. The DRA is fed through a slot coupled microstrip?transmission line?printed below the slot. The ridge-gap waveguide technology?(RGW) is used in the feeding layer to suppress the surface wave?surrounding the microstrip transmission line and improve the peak gain. The RGW?unit-cell structure has stop-band of 46–95?GHz. The SIW DRA introduces imped-ance bandwidth from 59.4 to 60.4?GHz (1.67% referenced to 60 GHz)?with peak gain of 6.78 dBi. The circular polarization (CP) is achieved by the rotation of the dog-bone shaped DRA by 45°?with respect to the feeding slot. It produces left-hand CP with a bandwidth of 0.22?GHz?(0.36%). A 2 × 1 SIW-DRA elements are designed with sequential rotation and phases for CP bandwidth enhancement. The peak gain increases to 9.1?dBi, and a broad-band AR of 4.8?GHz (8%) is achieved. 2 × 2 SIW-DRA elements with 90° orientation rota-tion angle and phases of 0, 90°, 180°, and 270° are designed. An improvement in the peak gain of 11?dBi is produced with wide AR bandwidth of 10.8?GHz?(18% from 54.2 GHz to 65?GHz) for 60?GHz communications.
关键词： DRA,Circular polarization,Substrate integrated waveguide (SIW),Ridge-gap structure
更新于2025-09-23 15:19:57
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Extraction of the terahertz constitutive tensors of multilayer graphene-dielectric stacks
摘要： In this paper, we present a reliable method to extract the electromagnetic constitutive tensors of complex synthesized multilayer graphene-dielectric stacks in the terahertz band. This macroscopic electromagnetic characterization method uses the transmission and reflection coefficients of a normal-incident circularly polarized electromagnetic wave on the material structure. The employment of circularly polarized waves has the advantage of overcoming the ambiguity at high frequencies attributed to the multi-branching discontinuities in the extracted permeability and permittivity tensors of natural or synthesized materials. The retrieved permeability and permittivity tensors are validated by the data obtained from analytical and numerical solutions of the original electromagnetic problem for the case of circularly polarized wave incidence.
关键词： Graphene-dielectric,Terahertz,Tensor extraction,Effective medium theory,Circular polarization
更新于2025-09-23 15:19:57
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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) - A Circularly Polarized Antenna Element Based on Open-ended Waveguide
摘要： Based on the open-ended rectangular waveguide structure, we proposed a circularly polarized antenna element with wide axial-ratio (AR) beam-width in this communication. Two rectangular notches are distributed on the wide sides of a rectangular waveguide in a 180° rotational symmetry to excite circular polarization. The simulated RHCP gain of the antenna is about 3.2 dBic at 11.5 GHz and the 3-dB AR beam-width is more than 120°. In addition, Owing to its simple configuration, the compact size (12(cid:2)(cid:2)6 mm2), this antenna element lays a good foundation for circularly polarized array antennas in wireless communication applications.
关键词： Circular polarization,End-fire antennas,Waveguide antennas,Wide beam-width
更新于2025-09-23 15:19:57
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Measurement method of axial ratio using only the reflection coefficient of waveguide circular polarizer
摘要： A circularly polarized feed circuit in a primary radiator of a reflector antenna is often required to have a low axial ratio. Therefore, it is necessary to accurately evaluate the axial ratio. The left- and right-handed circular polarized components are numerically obtained from the complex coefficients measured for dual linear polarized waves. The transmission phase measurement is difficult to measure accurately, particularly at high frequencies such as Ka band. Authors proposed a method to measure the axial ratio of the circular polarization feeding circuit from the reflection coefficient only, and the proposed method has been validated by the numerical simulation.
关键词： measurement,axial ratio,circular polarization,feed circuit
更新于2025-09-23 15:19:57
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Dual-circularly polarized patch antenna using simple isolation techniques and its array application
摘要： This paper presents low cost, low complexity, dual-circularly polarized patch antenna designs. The aperture coupled antennas employ simple square slotline loop elements to provide surface current cancellation in the critical regions of the antenna structure. High isolation (below 50 dB) is then obtained between the two antenna inputs, one for each polarization state. Circular polarization (CP) is produced thanks to the use of a planar hybrid coupler, feeding the antenna with two quadrature signals. Reciprocity of these components allows for the use of one port as the input (Tx) and the other one as an output (Rx), making the antenna work in full duplex mode. Also, both right-hand and left-hand circular polarizations are possible by interchanging the Tx and Rx ports, bringing a valuable degree of versatility. The proposed antenna design is also grouped in a 2x2 array for operation at C band (2.45 GHz), and its corresponding results are reported. Possible applications for the single-element and the low profile array include modern short range wireless communications, polarization diversity, direction finding, radar, and other beam steering array applications.
关键词： full duplex,circular polarization,aperture coupled,patch antenna,isolation
更新于2025-09-23 15:19:57
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Wide-angle scanning circular polarization phased array based on polarization rotation technology
摘要： A wide-beam circular polarization (CP) antenna and a wide-angle scanning phased array based on novel polarization rotation reflective surface (PRRS) are proposed. The CP wide-beam pattern is obtained by the combination of the radiation wave from the patch antenna and the orthogonal reflected wave from the PRRS with a 90(cid:1) phase difference. The proposed CP wide-beam antenna obtains the patterns with the 3-dB beamwidth more than 136(cid:1) and the axial ratio (AR) beamwidth more than 132(cid:1) in the xoz-plane. Furthermore, an eight-element phased array based on the wide-beam CP antenna element is also developed. The measured results show that the main beam of the array can scan from ?65(cid:1) to 65(cid:1) with a gain fluctuation less than 3 dB and the ARs at every scanning angle less than 3 dB.
关键词： polarization rotation,phased array,wide-beam,circular polarization,wide-angle scanning
更新于2025-09-19 17:15:36
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[IEEE 2018 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting - Boston, MA, USA (2018.7.8-2018.7.13)] 2018 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting - Wideband Circularly-Polarized 3D Antenna Array for Millimeter-Wave Applications
摘要： This paper presents a novel millimeter-wave wideband circularly-polarized 3D helical array antenna that works at 30 GHz. To design an antenna with wide circular polarization (CP) bandwidth, a 2 x 2 axial-mode helical structure is fed by using a sequential phase feeding network. The antenna array covers a wide frequency band from 26.4 GHz to 34 GHz with an achieved maximum gain of 11 dB and an axial ratio of less than 3 dB in the whole band. Moreover, the radiation pattern of the proposed antenna has a right-handed circular polarization (RHCP) with side-lobe level below -10 dB. Subsequently, the proposed antenna array can be a good candidate for millimeter-wave communication systems around 30 GHz.
关键词： 3D antenna,Antenna array,circular polarization (CP),helix,millimeter wave
更新于2025-09-19 17:15:36
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[IEEE 2018 18th Mediterranean Microwave Symposium (MMS) - Istanbul, Turkey (2018.10.31-2018.11.2)] 2018 18th Mediterranean Microwave Symposium (MMS) - Chiral SRR Metasurfaces for Circular Polarisation Conversion
摘要： A circular polarization dual band metamaterial polarization rotator composed of two double split ring resonators rotated 90o with respect to each other is presented. Asymmetric transmission between Txx and Tyy and symmetric transmission between Txy and Tyx has been achieved. The circular polarization is caused by the symmetric transmission between Txy and Tyx. The design has been demonstrated numerically at microwaves frequency. The structure holds promise for ultra-compact polarizing devices for any frequency range given the scalability of the approach.
关键词： Metasurfaces,Circular polarization,Chiral metamaterial,Split Ring Resonators
更新于2025-09-19 17:15:36
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[IEEE 2018 18th Mediterranean Microwave Symposium (MMS) - Istanbul, Turkey (2018.10.31-2018.11.2)] 2018 18th Mediterranean Microwave Symposium (MMS) - Systematic Design of a Circularly Polarized Microstrip Antenna Using a Shape Super-Formula and the Characteristic Mode Theory
摘要： The characteristic mode theory gives useful insights into the physical behavior of antennas, which can be used for the design of single-feed circularly polarized antennas. For example, an antenna with any geometrical shape may be systematically modified by the characteristic mode analysis to give circular polarization. In this paper, a procedure based on the characteristic mode theory is used for the design and modification of arbitrarily shaped antennas to produce a circularly polarized radiated field at 2.45 GHz for ISM band application. By using this procedure the axial ratio of a proposed antenna has dropped to 0.05 dB without the need of employing an optimization software.
关键词： Characteristic Mode,Super-formula,Modal Significance,Circular Polarization
更新于2025-09-19 17:15:36