Research On Dual-band Multi-polarized Shared-aperture Antenna Element And Array

Antenna is an essential part of wireless system.The design of antenna has become more and more demanding with the rapid development of modern communication technology,from a simple piece of metal to a complex component or even a system.Dual/multi-band and dual/multi-polarization antennas have also become an important development direction and have wide application value in synthetic aperture radar.The shared-aperture antenna can reduce the electromagnetic coupling between antennas of different frequencies by reasonable space layout,so that antennas of different frequencies can work under the same aperture.In addition,various methods are adopted to increase the isolation degree between the antennas of different bands.This paper designs a shared aperture antenna element and array that can work in different frequency bands and different polarization modes according to this demand.The main research contents are as follows:(1)A multi-polarization shared-aperture antenna element with in P/S dual-band is proposed.The approximate size of the antenna in each frequency band can be obtained through theoretical calculation,and then the specific size of the structure can be determined through simulation.The low band antenna has the advantage of low cross-polarization.The circular microstrip antenna operating in the high band adopts two feed points for feeding,and the main polarization of the antenna can be switched to left-handed circularly polarization(LCP),right-handed circularly polarization(RCP)and linearly polarization(LP)freely by changing the amplitude and phase of the two feed points.By placing the S-band antenna in a cylindrical metal cavity,the isolation between the antennas is increased.Finally,the feasibility of the designed antenna structure is further verified through practical processing and testing.(2)A multi-polarized shared-aperture antenna array working in L/S dual-band is proposed.The specific size corresponding to the working center frequency of the antenna is obtained through theoretical calculation and simulation verification.In order to make the L-band rectangular antenna and the S-band circular antenna share the same aperture and form an array,we designed four L-band antenna elements.And place four S-band antennas of the same size around each L-band antenna.Finally,a 2*2 array of L-band and a 4*4 array structure of S-band were formed.The L-band antenna uses four feed points for feeding,and the S-band antenna also uses four feed points for feeding.Both band antennas can achieve flexible control of the main polarization from LCP to RCP.