Research On Circular Polarization Selection Surface's Application On Multi-function Reflectarray

Reflectarray antenna,combining the advantages of both parabolic antenna and phased array antenna,is the main research direction of long-distance high-gain antenna.Multi-function reflectarray with polarization or frequency multiplexing,can further reduce size and costs and has important practical value in the field of wireless communication,especially satellite antenna.But multi-function reflectarray is also a research challenge.With the application of circular polarization selection surface(CPSS)to the reflectarray,the selection of circularly polarized(CP)wave combined with beam controlling is achieved,which has become an important emerging direction in the multi-functional research on the circularly polarized reflectarray.But the single working mode of current CPSS limits the development of CPSS-based multi-function reflectarray.This paper focuses on the requirement for multi-function reflectarray and the limitation of single-function CPSS,and studies the application of new CPSS to the multi-function reflectarray gradually.It mainly consists of three parts: design of double circularly polarized reflectarray based on traditional CPSS and the beamforming,research on the function extension of CPSS and study of multi-function CP reflectarray based on dual-mode CPSS.The main work and innovations of this paper are as follows:(1)In order to solve the problem of low-efficiency in dual-CP and difficulty in beamforming,a high efficiency dual-CP reflectarray is designed based on the traditional CPSS unit and the beamforming is realized.By applying the CP selection function of CPSS to the reflecarray,the independent control of the dual-CP incident wave is realized.When the dual-CP waves illuminate separately,the peak gains of the different pointing beam are both more than 25 dBi,the efficiency are 49.7% and 49.3%,respectively(the efficiency of the existing double circularly polarized reflectarray is only 25%),and a consistent radiation pattern with the corresponding single-layer array working separately is achieved.Based on this array,the beamforming in dual-CP is realized for the first time.When the incident wave is LHCP or RHCP,the gain reaches 14 dBi or 16 dBi,respectively in the target beamforming area.The cross-polarization levels of the CPs in the target beamforming area are less than-20 dB.(2)Aiming at solving the single-function problem of traditional CPSS,three kinds of function extension in dual-band,dual-mode and dual-CP is studied.By using the implementation method for multiband monopole antenna,a slot loaded dual-band CPSS is designed,and performs the same CP selection in X\Ku band.A single resonator dual-mode CPSS was designed by using high-order resonant mode of the metal strip,which displays LHCPSS(left-handed circular polarization selection surface)in one mode,and displays RHCPSS(right-handed circular polarization selection surface)in the other mode.Based on the reconfigurable antenna,a dual-CP reconfigurable CPSS is designed,which can be used to realize LHCPSS and RHCPSS conversion in the same band by using switching device.Both reflection coefficient and transmission coefficient of the proposed three multifunctional CPSS structure for the target circularly polarized wave are greater than-1dB in respective operating bands and good CP selection is presented.(3)In order to solve difficult in the complex structure and less multi-function achievements in reflectarray,a dual-mode CPSS unit which can be applied to CP reflectarray is proposed for the first time,based on CPSS multi-function research.Single-layer dual-band CP reflectarray based on dual-mode CPSS unit is designed and fabricated.The efficiencys are 41.2% and 55.5% at 11.6GHz and 14.6GHz,respectively.And the low axial ratio is presented in the corresponding 1dB-gain bandwidth.The dual-band performance and the structure are superior to the related research results.Based on the principle of the proposed dual-band reflectarray and dual-CP reflectarray,the realization method for dual-band dual-CP reflectarray is put forward for the first time,the feasibility is studied either,which is of great significance for research on multi-function reflectarray.