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 them can be obtained, without time-consuming 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.