Isolation Enhancement and Radar Cross Section Reduction of MIMO Antenna With Frequency Selective Surface

In this communication, a new frequency selective surface (FSS)-based isolation technique is proposed for multiple-input-multiple-output (MIMO) antennas. In the proposed method, a conventional ground plane of monopole-based MIMO antenna is replaced with FSS to improve the isolation between the antenna elements as well as to reduce MIMO antenna radar cross section (RCS). In this communication, two FSS designs have been presented, and they are named as FSS and M_FSS. M_FSS is a slightly modified version of FSS. With FSS, isolation enhancement and RCS reduction have been achieved by altering antenna characteristics. With M_FSS, the same can be achieved by preserving the antenna characteristics. The RCS reductions of 25 and 20 dBsm have been achieved by replacing the PEC ground plane with FSS and M_FSS, respectively. Also, by using the proposed FSS, a stable RCS reduction up to 60° for TE polarization and up to 45° for TM polarization has been achieved. The proposed MIMO antenna with FSS has been fabricated, and the simulation results are experimentally verified.