Mutual Coupling Reduction of Slot Antenna Array by Controlling Surface Wave Propagation

In this communication, we present a methodology to reduce mutual coupling in a planar slot antenna array by using electric metamaterial. The proposed methodology is based on resisting and steering the propagation of surface wave. Initially, an array of complementary split-ring resonator (CSRR) is designed between the two slots for suppressing the surface wave propagation. Afterward, to steer the surface wave propagation, complementary fishnet structures are designed on the two sides of the slot array. Finally, for a better level of isolation improvement, both CSRR and complementary fishnet structures are simultaneously used. The final design has achieved at least 14 dB improvements in isolation level throughout the wide operating bandwidth of around 2 GHz, even if the gap between the slots is only 3.4 mm. The efficiency and the realized gain of the proposed antenna have also been studied. Because of the use of both metamaterial structures as a complementary, the overall configuration becomes fully planar and easy to realize.