Asymmetrical Low-RCS FSS-Based Antenna for Tri-Band Shared-Aperture Array

This letter proposes an asymmetrical low-radar cross section (RCS) frequency selective surface (FSS)-based low band (LB: 1.7-2.7 GHz) antenna for the application in tri-band shared-aperture array. In the array, high band 1 (HB1: 3.3-3.8 GHz) antennas and HB2 (4.8-5 GHz) antennas are distributed on the two sides of the asymmetric LB antenna with four FSS unit cells. The bandpass property of the FSS unit cell is formed after inserting a patch into the square loop, meanwhile, it can be controlled by cutting the patch into more pieces. To respectively suppress the blockage effect of the LB antenna on the two-side HB1 and HB2 antennas, a low-RCS FSS-based LB antenna is constructed asymmetrically by placing two kinds of low-RCS FSS unit cells with different patch pieces. Importantly, the low-RCS characteristic of the FSS unit cells on both bands and LB working performance can be independently controlled, so that good performance for both of them can be obtained, without timeconsuming optimization. Finally, the LB blockage effect on the entire HB1 and HB1 has been significantly reduced as expected and good agreement is achieved between the simulation and experiment.