Compact Waveguided Metamaterials for Suppression of Mutual Coupling in Microstrip Array

In this paper, suppression of mutual coupling is achieved using compact waveguided metamaterials (WG-MTMs) in between elements of a densely packed microstrip array. Both the E-plane internally folded complementary split ring resonator and the H-plane internally folded complementary split ring resonator are employed to reduce the mutual coupling between adjacent elements. Coupling suppression of 18 dB and 9 dB, for elements in the E-plane and H-plane, respectively, is demonstrated. Due to the compact size of the waveguided metamaterials, the edge-to-edge separation between elements is kept at only 0.093λ0. With the same element spacing, a 2 × 2 array is also simulated with compact WG-MTMs. The proposed structure reduces the array size and enables the implementation of compact Multiple-Input-Multiple-Output systems.