Mutual Coupling and RCS Reduction of MIMO Antenna using a hybrid technique

In this paper, simultaneous reduction of radar cross section (RCS) and mutual coupling in MIMO antennas have been achieved by creating modifications in the conventional MIMO design at 3.97 GHz. The antenna element comprises a F-shaped microstrip patch antenna backed by copper grounded FR4 substrate. The edge spacing between the antennas is kept minimal for maintaining compactness which causes very high mutual coupling. A novel structure for MIMO has been proposed by introducing a T shaped stub equidistant from each of the edges of the antenna elements. Further, a defected ground structure (DGS) with L shaped slot surrounded by band-stop FSS unit cells has been employed for causing 13 dB of mutual coupling and 18 dB of radar cross section (RCS) reduction in the proposed antenna as compared to conventional MIMO. The structures of antennas, parasitic stubs and frequency selective surfaces have been analysed and numerically studied using CST Microwave Studio 2020.