Geometrical Optics-Based Advanced Design of an Open Cavity Resonant Antenna
TL;DR: In this paper, geometrical optics-based raytracing was combined with modal analysis to realize an open cavity structure as an advanced variant of the resonant cavity antenna (RCA).
Abstract: This letter explores geometrical optics-based raytracing in combination with modal analysis to realize an open cavity structure as an advanced variant of the resonant cavity antenna (RCA). Additional ray confinement has been ensured by determining accurate phase-locking conditions as demonstrated for the first time. Its combination with the analysis of the cavity mode has also been introduced to determine the optimum design parameters, achieving improved radiation properties. With respect to a reference RCA reported earlier, the proposed approach exhibits a remarkable improvement in gain by 4–9 dB, resulting in about 17 dBi peak value consistently over the full 18% matching bandwidth. This is resultant from an increase in aperture efficiency, typically from 27% to 74%. This is achieved without any compromise with the cross-polarization property. The sidelobe level improves over the band except in higher frequency in H-plane. The proposed concept is commercially viable, showing significantly advantageous features.
Citations
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01 Jan 2022
TL;DR: This study examined to what degree performance on WAIS-IV verbal subtests predicts performance on executive functioning measures (Trails Making-B, Category, and Wisconsin Card Sort Test) and found Categories is the best predictor.
Abstract: The
7 citations
DOI•
TL;DR: In this paper , a Fabry-Perot cavity antenna (FPCA) is proposed to achieve wide common impedance and gain bandwidth along with high gain, which is achieved by employing a printed primary radiator and superstrate with superior manufacturing capabilities.
Abstract: An advanced design of a Fabry–Perot cavity antenna (FPCA) is proposed to achieve wide common impedance and gain bandwidth along with high gain. A compact and lightweight FPCA is achieved by employing a printed primary radiator and superstrate with superior manufacturing capabilities. A wideband primary radiator is employed for the first time to realize such a wideband FPCA. Superstrate dimensions are estimated by using the aperture field theory and the proposed design is validated through both EM simulation and experiment. The measured broadside gain is shown to be better than 11.5 dBi over an impedance bandwidth of 63% (8.2−15.6 GHz). About 40% common impedance and gain bandwidth is achieved while the broadside gain attains a maximum value of 17.4 dBi. To the best of our knowledge, this has never been achieved before from an FPCA made of a printed superstrate and a primary radiator. The cross-polar (XP) radiation remains under −40 dB whereas the front-to-back ratio remains above 35 dB, over the desired bandwidth.
TL;DR: In this article , a Fabry-Perot cavity antenna (FPCA) is proposed to achieve wide common impedance and gain bandwidth along with high gain, which is achieved by employing a printed primary radiator and superstrate with superior manufacturing capabilities.
Abstract: An advanced design of a Fabry–Perot cavity antenna (FPCA) is proposed to achieve wide common impedance and gain bandwidth along with high gain. A compact and lightweight FPCA is achieved by employing a printed primary radiator and superstrate with superior manufacturing capabilities. A wideband primary radiator is employed for the first time to realize such a wideband FPCA. Superstrate dimensions are estimated by using the aperture field theory and the proposed design is validated through both EM simulation and experiment. The measured broadside gain is shown to be better than 11.5 dBi over an impedance bandwidth of 63% (8.2−15.6 GHz). About 40% common impedance and gain bandwidth is achieved while the broadside gain attains a maximum value of 17.4 dBi. To the best of our knowledge, this has never been achieved before from an FPCA made of a printed superstrate and a primary radiator. The cross-polar (XP) radiation remains under −40 dB whereas the front-to-back ratio remains above 35 dB, over the desired bandwidth.
DOI•
TL;DR: In this paper , a dual wideband compact shared-aperture microstrip patch/Fabry-Perot resonator cavity antenna is proposed for dual-band point-to-point line-of-sight (LOS)/non-LOS (NLOS) communication systems.
Abstract: In this article, a dual wideband compact shared-aperture microstrip patch/Fabry–Perot resonator cavity antenna is proposed. A reflective meshed patch is designed to conduct as the shared surface, which works as the radiator at the lower band but the partial reflective sheet (PRS) at the upper band. A transmissive meshed patch is designed as the parasitic element to broaden the lower bandwidth without influence on the upper band radiation. The shaped ground is used to improve the front-to-back ratio at the lower band while maintaining a compact size. Moreover, the reflective meshed patch, which is built by two complementary frequency selective structures (FSSs), shows a positive reflection phase gradient to broaden the bandwidth of the antenna at the upper band without influence on the lower band radiation. The measurements reveal that a common bandwidth of ( $\vert \text{S}_{11(22)}\vert < -10$ dB, gain reduction < 3 dB) 25.4% and 21.3%, an isolation higher than 40 and 22 dB, a peak gain of 9.01 and 16.6 dBi at UHF band and C-band are achieved, respectively. The above properties make the proposed antenna suitable for dual-band point-to-point line-of-sight (LOS)/non-LOS (NLOS) communication systems.
10 Jul 2022
TL;DR: In this paper , all kinds of Hybrid DRA explored in the last two decades including some state-of-the-art techniques are discussed. But the authors focus on the hybrid DRA design.
Abstract: Dielectric resonator antenna (DRA) will complete 40 years since its inception in 1983 and has accumulated several novel techniques and designs to serve various applications. ‘Hybrid DRA’ is one of them, conceived more than 20 years ago. This paper is aimed to portray all kinds of Hybrid DRAs explored in the last two decades including some state-of-the-art techniques.
References
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TL;DR: In this paper, the authors investigated the effect of placing a partially reflecting sheet in front of an antenna with a reflecting screen at a wavelength of 3.2 cm and showed that large arrays produce considerably greater directivity but their efficiency is poor.
Abstract: Multiple reflections of electromagnetic waves between two planes are studied, and the increase in directivity that results by placing a partially reflecting sheet in front of an antenna with a reflecting screen is investigated at a wavelength of 3.2 cm. The construction and performance of various models of such arrays is discussed. Thus, for example, a "reflex-cavity antenna" with an outer diameter of 1.88 \lambda and an over-all length of only 0.65 \lambda is described which has half-power beamwidths of 34\deg and 41\deg in the E and H planes, respectively, and a gain of approximately 14 db. It is shown that larger systems produce considerably greater directivity but that their efficiency is poor.
977 citations
TL;DR: The method is extended to produce narrow patterns about the horizon, and directive patterns at two different angles, and the bandwidth limitation of the method is discussed.
Abstract: Resonance conditions for a substrate-superstrate printed antenna geometry which allow for large antenna gain are presented. Asymptotic formulas for gain, beamwidth, and bandwidth are given, and the bandwidth limitation of the method is discussed. The method is extended to produce narrow patterns about the horizon, and directive patterns at two different angles.
594 citations
TL;DR: In this article, a leaky-wave analysis is used to explain the narrow-beam resonance gain phenomenon in which narrow beams may be produced from a printed antenna element in a substrate-superstrate geometry.
Abstract: A leaky-wave analysis is used to explain the narrow-beam resonance-gain phenomenon in which narrow beams may be produced from a printed antenna element in a substrate-superstrate geometry. It is demonstrated that the phenomenon is attributable to the presence of both transverse electric and transverse magnetic-mode leaky waves, that are excited on the structure. Asymptotic formulas for the leaky wave are compared with the exact patterns to demonstrate the dominant role of the leaky waves in determining the pattern. Results are presented as a function of frequency, the scan angle, and the permittivity of the superstrate. >
343 citations
TL;DR: In this paper, two different defects, one introduced by the ground plane of the antenna and the other produced by a row of defect rods with different dielectric constants in the EBG structure, are simultaneously used as key controllers of directivity enhancement.
Abstract: We present some applications of an electromagnetic bandgap (EBG) superstrate as a spatial angular filter for filtering undesired radiation by sharpening the radiation pattern. Two different defects, one introduced by the ground plane of the antenna and the other produced by a row of defect rods with different dielectric constants in the EBG structure, are simultaneously used as key controllers of directivity enhancement. Initially, we study the unit cell of the EBG structures by varying several parameters, in order to understand how they influence the locations of the bandgap and defect frequencies. Next, the defect frequencies of the unit cell of the EBG cover, and those with high directivity for the EBG antenna composite, are compared to validate the proposed design scheme. Finally, we introduce some interesting applications of EBG superstrates for various types of patch antennas as spatial angular filters, such as a dual-band orthogonally-polarized antenna, a wide-band directive antenna, and an array antenna with grating lobes.
260 citations
TL;DR: In this article, a miniature aperture-coupled microstrip antenna of very high permittivity designed at 1.66 GHz is described, where superstrates of appropriate thickness are added on the substrate for gain enhancement.
Abstract: A miniature aperture-coupled microstrip antenna of very high permittivity designed at 1.66 GHz is described. Superstrates of appropriate thickness are added on the substrate for gain enhancement. Its size is dramatically reduced and the electrical performance remains almost the same as compared with the conventional microstrip antenna of low dielectric constant. Experimental data for the return loss, radiation pattern and measured antenna gain are presented to validate the design.
207 citations