Metasurface Superstrate-based MIMO Patch Antennas with Reduced Mutual Coupling for 5G Communications

Multiple-input multiple-output (MIMO) systems have several advantages, such as providing high capacity, spatial diversity, etc. MIMO antennas suffer with high mutual coupling (m-coupling) between the ports. In this paper, the metasurface with negative permeability (MNG) is designed and utilized for m-coupling reduction of a two-port rectangular microstrip MIMO antenna (Antenna 1). Two metasurface superstrate-based MIMO antennas with reduced m-coupling for fifth generation (5G) are proposed. The first design (Antenna 2) is constructed using a single metasurface superstrate suspended above the two-port MIMO microstrip antenna. The second design (Antenna 3) is constructed using a double metasurface superstrate layers suspended above the two-port MIMO microstrip antenna. Both metasurface-based MIMO antennas achieve significant m-coupling reduction over the entire bandwidth. The edge-to-edge separation between the two patches is 0.29λ0. The proposed Antenna 3 obtains the reduced m-coupling of −44 dB along with the wide bandwidth of 5.92−6.2 GHz and a maximum gain of 6.79 dB. The proposed antennas are suitable for extended sub-6 GHz 5G applications with the operating frequency band of 5.9–6.1 GHz.