Multi-channel terahertz focused beam generator based on shared-aperture metasurface

Most of existing metasurfaces usually have limited channel behavior,which seriouslyhinders their development and application.In this paper,we propose a multi-channel terahertz focused beam generator based on shared-aperture metasurface,and the generator consists of a top square metal strip,a middle layer of silica and a metal bottom plate.By changing the position and size of the shared-aperture array,the designed metasurface can generate any number of multi-channel focusing beams at different predicted positions.In addition,the energy intensity of focusing beams can be controlled.The full-wave simulation results show that the metasurface achieves four-channel vortex focused beam generation with different topological charges,and five-,six-,eight-channel focused beam generation with different energy intensities at a frequency of 1 THz,which are in good agreement with the theoretically calculated predictions.This work can provide a new idea for designing the terahertz multichannel devices.

Progress in dual-band dual-polarization shared-aperture SAR antennas

The progress in dual-band dual-polarization(DBDP)shared-aperture antennas for the synthetic aperture radar(SAR)application in the last decade is reviewed.Several designs of DBDP SAR antenna arrays are introduced with their main performances,then their comparison is summarized.In addition,some techniques enhancing DBDP antenna performances are presented.

A low-profile dual-broadband dual-circularly-polarized reflectarray for K-/Ka-band space applications

A low-profile dual-broadband dual-circularly-polarized(dual-CP)reflectarray(RA)is proposed and demonstrated,supporting independent beamforming for right-/left-handed CP waves at both K-band and Ka-band.Such functionality is achieved by incorporating multi-layered phase shifting elements individually operating in the K-and Ka-band,which are then interleaved in a shared aperture,resulting in a cell thickness of only about O.1az.By rotating the designed K-and Ka-band elements around their own geometrical centers,the dual-CP waves in each band can be modulated separately.To reduce the overall profile,planar K-/Ka-band dual-CP feeds with a broad band are designed based on the magnetoelectric dipoles and multi-branch hybrid couplers.The planar feeds achieve bandwidths of about 32%and 26%at K-and Ka-band respectively with reflection magnitudes below-13 dB,an axial ratio smaller than 2 dB,and a gain variation of less than 1 dB.A proof-of-concept dual-band dual-CP RA integrated with the planar feeds is fabricated and characterized which is capable of generating asymmetrically distributed dual-band dual-CP beams.The measured peak gain values of the beams are around 24.3 and 27.3 dBic,with joint gain variation<1 dB and axial ratio<2 dB bandwidths wider than 20.6%and 14.6%at the lower and higher bands,respectively.The demonstrated dual-broadband dual-CP RA with four degrees of freedom of beamforming could be a promising candidate for space and satellite communications.