A Decoupling Structure for Mutual Coupling Suppression in Stacked Microstrip Patch Antenna Array

A simple decoupling structure for a stacked microstrip patch antenna array is proposed. By loading a shorting C-shaped structure and a square ring, the mutual coupling between stacked microstrip patch antenna elements can be adjusted at the low- and high-resonant frequencies, respectively. To verify the feasibility of the proposed decoupling structure, the two-element stacked microstrip patch antenna arrays with and without decoupling structure are implemented and analyzed, respectively. Measured results indicate that the isolation between stacked microstrip patch antenna elements with the decoupling structure is enhanced by 10 dB as compared to the original structure with the free-space half-wavelength spacing at the center frequency.