Dual-Frequency Two-Element Antenna Array with Suppressed Mutual Coupling

An efficient technique utilizing the defected ground structure (DGS) to suppress the mutual coupling effect of a dual-frequency microstrip antenna array is studied. The proposed dual-frequency DGS beneath two patches includes two circular split ring slots, each of which corresponds to one resonant frequency of the patches. The characteristic of the compact DGS is theoretically and experimentally investigated. The prototypes of the patches arrays with and without the proposed DGS are fabricated. Both the simulated and measured results show that the mutual coupling between array elements has been obviously reduced at the two operating frequency bands with the implementation of the proposed DGS structure.