scholarly journals Novel phase distributions for large electronically beam-scanning reflectarrays

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ahad Sheikholeslami ◽  
Zahra Atlasbaf
Keyword(s):  
Phase Distribution ◽  
Symmetry Plane ◽  
Vertical Plane ◽  
Main Beam ◽  
The Novel ◽  
Beam Scanning ◽  
Hybrid Combination ◽  
Reflectarray Antenna ◽  
Phase Symmetry ◽  
Constant Phase Elements

AbstractIn this paper, the hybrid combination of genetic algorithm and particle swarm optimization (GAPSO) is used to optimize the phase distribution (PD) of beam-scanning reflectarray. The GAPSO takes advantage of both conventional algorithms and it could cover their weaknesses. Two novel PDs are proposed in this paper which constant phase elements (CPEs) and ordinary elements (OEs) are two basic kinds of elements used in them. The phases of CPEs are fixed and it is not changed during beam scanning and only OEs’ phase could be adjusted to scan the main beam. In this work GAPSO and two novel PDs are applied to array factor’s PD of a 30 × 30 reflectarray antenna to displace the main beam electronically in the vertical plane from − 40° to 40°. Also, in these two novel PDs, 28.8% of total elements are selected as CPEs. In the first one with only CPEs, the phase of OEs (71.2% of total elements) could adjust, but in the second novel PD with CPEs and phase symmetry plane 35.5% of the total elements’ phase could be changed to scan the beam. Optimization results show that the novel PD and hybrid algorithm have appropriate performance in the electronically beam scanning of reflectarrays.

scholarly journals Novel Phase Distributions for Large  Beam- Scanning Reflectarrays

2021 ◽  
Author(s):  
AHAD SHEIKHOLESLAMI ◽  
ZAHRA ATLASBAF
Keyword(s):  
Phase Distribution ◽  
Symmetry Plane ◽  
Vertical Plane ◽  
Main Beam ◽  
The Novel ◽  
Beam Scanning ◽  
Hybrid Combination ◽  
Reflectarray Antenna ◽  
Phase Symmetry ◽  
Constant Phase Elements

Abstract In this paper, the hybrid combination of genetic algorithm and particle swarm optimization (GAPSO) is used to optimize the phase distribution (PD) of beam-scanning reflectarray. The GAPSO takes advantage of both conventional algorithms and it could cover their weaknesses. Two novels PDs are proposed in this paper. Constant phase elements (CPEs) and ordinary elements (OEs) are two basic kinds of elements used in these two novel PDs. The phases of CPEs are fixed and it is not changed during beam scanning and only OEs’ phase could be adjusted to scan the main beam. GAPSO and two novels PDs are applied to array factor PD of a 30*30 reflectarray antenna to displace the main beam electronically in the vertical plane from-40⁰ to 40⁰. In these two novel PDs, 28.8% of total elements are selected as CPEs. In the first one with only CPEs, the phase of OEs (71.2% of total elements) could adjust, but in the second novel PD with CPEs and phase symmetry plane 35.5% of the total elements’ phase could be changed to scan the beam. Optimization results show that the novel PD and hybrid algorithm have appropriate performance in the electronically beam scanning of reflectarrays.

Beam-Scanning Lens Antenna Based on Elliptical Paraboloid Phase Distribution Metasurfaces

2019 ◽  
Vol 18 (8) ◽  
pp. 1562-1566
Author(s):  
Hao-Fang Wang ◽  
Zheng-Bin Wang ◽  
Zhi-Hang Wu ◽  
Ye-Rong Zhang
Keyword(s):  
Phase Distribution ◽  
Beam Scanning ◽  
Lens Antenna ◽  
Scanning Lens ◽  
Elliptical Paraboloid

scholarly journals Real-Time Mode Switching and Beam Scanning of High-Gain OAM Waves Using a 1-Bit Reconfigurable Reflectarray Antenna

Electronics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 2181
Author(s):  
Ziyang Wang ◽  
Xiaotian Pan ◽  
Fan Yang ◽  
Shenheng Xu ◽  
Maokun Li
Keyword(s):  
Real Time ◽  
Dimensional Space ◽  
Large Angle ◽  
High Gain ◽  
Mode Switching ◽  
Effective Control ◽  
Vortex Beam ◽  
Beam Scanning ◽  
The Future ◽  
Reflectarray Antenna

A reconfigurable electromagnetic surface has been studied to realize the adjustable orbital angular momentum (OAM) beams for real-time wireless communication and dynamic target detection in the future. OAM mode switching realized by many previous designs suffers from low gains without OAM beam scanning. In this article, a 1-bit reconfigurable reflectarray antenna is designed, fabricated, and tested for the real-time control of OAM mode switching and large-angle vortex beam scanning in three-dimensional space. The proposed reflectarray surface is composed of 1-bit electronically reconfigurable cells, and the size is 24 λ × 24 λ with 2304 units. The reconfigurable element is designed by using a radiation patch loading a PIN diode with effective control of two states, “ON” and “OFF”, for the demand of 180° phase difference. The reflectarray surface can be assigned to a code sequence of 0 or 1 by the Field-Programmable Gate Array (FPGA) in real time. Henceforth, the coding surface can dynamically control the generation of high-gain OAM beams, where only the optimized phase distributions on the surface need to be changed according to demand. To verify the concept, a large-scale reflectarray surface is fabricated and measured with an oblique feed at 15°. Different OAM-carrying phase distributions for different OAM beam states are calculated and tested. The test results show that the OAM mode switching between l = 1 and l = 2 is realized, and other variable modes such as l = 3 or l = 5 can also be achieved by modifying the phase encoding sequence. Furthermore, the direction of the vortex beams can be accurately controlled with gains over 20 dBi, and the large-angle vortex beam scanning is verified. Therefore, all results demonstrate that the proposed 1-bit reconfigurable reflectarray is efficient for the regulation and control of OAM-carrying beams for the demand of real-time dynamic wireless communications in the future.

Explicit analytic expression for normal moveout from horizontal and dipping reflectors in weakly anisotropic media of arbitrary symmetry type

Geophysics ◽  
2000 ◽  
Vol 65 (4) ◽  
pp. 1294-1304 ◽  
Author(s):  
P. N. J. Rasolofosaon
Keyword(s):  
Wave Velocity ◽  
Symmetry Plane ◽  
Vertical Plane ◽  
Anisotropic Media ◽  
P Wave ◽  
Symmetry Type ◽  
Seismic Reflection Data ◽  
General Symmetry ◽  
P Wave Velocity ◽  
Analytic Expression

When processing and inverting seismic reflection data, the NMO velocity must be correctly described, taking into account realistic situations such as the presence of anisotropy and dipping reflectors. Some dip‐moveout (DMO) algorithms have been developed, such as Tsvankin’s analytic formula. It describes the anisotropy‐induced distortions in the classical isotropic cosine of dip dependence of the NMO velocity. However, it is restricted to the vertical symmetry planes of anisotropic media, so the technique is unsuitable for the azimuthal inspection of sedimentary rocks, either with horizontal bedding and vertical fractures or with dipping bedding but no fractures. However, under the weak anisotropy approximation the deviations of the rays from a vertical plane can be neglected for the traveltimes computation, and the equation can still be applicable. Based on this approach, an explicit analytic expression for the P-wave NMO velocity in the presence of horizontal or dipping reflectors in media exhibiting the most general symmetry type (triclinic) is obtained in this work. If the medium exhibits a horizontal symmetry plane, the concise DMO equations are formally identical to Tsvankin’s except that the parameters δ and ε are not constant but depend on the azimuth ψ Physically, δ(ψ) is the deviation from the vertical P-wave velocity of the P-wave NMO velocity for a horizontal reflector normalized by the vertical P-wave velocity for the azimuth ψ. The function ε(ψ) has the same definition as δ(ψ) except that the P-wave NMO velocity is replaced by the horizontal P-wave velocity. Both depend linearly on (1) new dimensionless anisotropy parameters and (2) generalizing to arbitrary symmetry the transversely isotropic parameters δ and ε. In the most general symmetry case (triclinic), an additional term to the DMO formula is necessary. The numerical examples, based on experimental data in rocks, show two things. First, the magnitude of the DMO errors induced by anisotropy depends primarily on the absolute value of ε(ψ) − δ(ψ) and not on the individual values of ε(ψ) and δ(ψ), which is a direct consequence of the similarity between Tsvankin’s equation and the equation presented here. Second, the anisotropy‐induced DMO correction can be significant even in the presence of moderate anisotropy and can exhibit complex azimuthal dependence.

scholarly journals Comparative analysis of cylindrical and planar aesa in 3d suveillance radar.

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Dragan Paunović ◽  
Keyword(s):  
Comparative Analysis ◽  
Vertical Plane ◽  
Optimal Solution ◽  
Main Beam ◽  
Advantages And Disadvantages ◽  
Near Zone ◽  
Constant Shape ◽  
Mechanical Rotation ◽  
Original Configuration ◽  
Selection Of

A modern rotating 3D surveillance radars scan azimuth by mechanical rotation, and scan elevation using Active Electronic Scanning Array (AESA) in Multi Beam Receive Mode (MBM). Radars with fixed cylindrical AESA and four-sided prismatic antenna, with 4 flat AESA, scan azimuth electronically, without mechanical rotation. The most significant advantage of electronic scanning is the possibility of Multi-mode operation: surveillance targets in the far zone and targeting targets in the near zone. However, electronic scanning also brings problems. A main beam of planar AESA spreads and lateral lobes increase when the radiating direction increases. An original arrangement of shifted array to reduce lateral lobes has been proposed. The cylindrical array has a constant shape of pattern during azimuth scanning. But, for both prismatic and cylindrical AESA, the beam deforms during scanning in vertical plane, so limits the elevation scan. Also, the complexity and price of fixed AESA is significantly higher compared to the rotating one. In order to enable the selection of the optimal solution for a specific application, the comparative analysis of advantages and disadvantages for cylindrical, prismatic and rotating AESA is done. The original configuration of the cylindrical AESA for Very Fast Scanning in Near-zone has been proposed.

scholarly journals A Phase Distribution Network Using 2 × 4 Butler Matrix for Linear/Planar Beam-Scanning Arrays

IEEE Access ◽  
2021 ◽  
Vol 9 ◽  
pp. 133438-133448
Author(s):  
Huy Nam Chu ◽  
The Hop Hoang ◽  
Kai-Jun Ji ◽  
Tzyh-Ghuang Ma
Keyword(s):  
Phase Distribution ◽  
Distribution Network ◽  
Beam Scanning ◽  
Butler Matrix

scholarly journals GO Shaping of Omnidirectional Dual-Reflector Antennas with Arbitrary Main-Beam Direction in Elevation Plane by Connecting Conic Sections

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Rafael A. Penchel ◽  
Sandro R. Zang ◽  
José R. Bergmann ◽  
Fernando J. S. Moreira
Keyword(s):  
Method Of Moments ◽  
Phase Distribution ◽  
Main Beam ◽  
Hybrid Technique ◽  
Mode Matching ◽  
Conic Sections ◽  
Beam Direction ◽  
Reflector Antennas ◽  
Bodies Of Revolution ◽  
Shaping Procedure

This work discusses an alternative geometrical optics (GO) technique to synthesize omnidirectional dual-reflector antennas with uniform aperture phase distribution together with an arbitrary main-beam direction for the antenna radiation pattern. Sub- and main reflectors are bodies of revolution generated by shaped curves defined by local conic sections consecutively concatenated. The shaping formulation is derived for configurations like ADC (axis-displaced Cassegrain) and ADE (axis-displaced ellipse) omnidirectional antennas. As case studies, two configurations fed by a TEM coaxial horn are designed and analyzed by a hybrid technique based on mode matching and method of moments in order to validate the GO shaping procedure.

scholarly journals Compact solid-state optical phased array beam scanners based on polymeric photonic integrated circuits

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sung-Moon Kim ◽  
Eun-Su Lee ◽  
Kwon-Wook Chun ◽  
Jinung Jin ◽  
Min-Cheol Oh
Keyword(s):  
Solid State ◽  
Integrated Circuits ◽  
Phased Array ◽  
Phase Distribution ◽  
Bragg Reflector ◽  
Free Space Optical ◽  
Beam Scanning ◽  
Optical Links ◽  
Polymer Waveguide ◽  
Optical Phased Array

AbstractOptical phased array (OPA) devices are being actively investigated to develop compact solid-state beam scanners, which are essential in fields such as LiDAR, free-space optical links, biophotonics, etc. Based on the unique nature of perfluorinated polymers, we propose a polymer waveguide OPA with the advantages of low driving power and high optical throughput. Unlike silicon photonic OPAs, the polymer OPAs enable sustainable phase distribution control during beam scanning, which reduces the burden of beamforming. Moreover, by incorporating a tunable wavelength laser comprising a polymer waveguide Bragg reflector, two-dimensional beam scanning is demonstrated, which facilitates the development of laser-integrated polymeric OPA beam scanners.

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