Isolation Enhancement and Radar Cross Section Reduction of MIMO Antenna

What is it about?

In this paper, 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 paper, 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 dBsm 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.

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Why is it important?

RCS is an important parameter, and it needs to be maintained low in defense and military applications. By incorporating antennas in these applications, RCS increases due to the presence of a conductive ground plane in the antenna structure. MIMO antennas can increase War fighter’s capabilities in military and defense applications and so they are finding a place in these areas by replacing conventional antennas. Thus, it is important to have a technique to achieve RCS reduction of MIMO antenna. In this paper, by replacing PEC ground plane with FSS, RCS reduction of MIMO antenna has been achieved. Up to 600 incident angle for TE polarization and up to 450 incident angle for TM polarization, stability in the RCS reduction can be observed in this paper. The used FSS not only reduces RCS but it also enhances the isolation between the antenna elements.