A hybrid solution for mutual coupling reduction between closely spaced microstrip antennas

A hybrid solution is proposed to reduce mutual coupling between closely spaced microstrip antennas, which is realized by a metallic wall combined with two open-ended slots. This combination structure, occupying a small spacing between antenna elements, achieves a satisfactory isolation, which is validated by the simulation and measurement. The results indicate that the acquired isolation is better than 20 dB, characterized by a dip of 33.2 dB, with an edge-to-edge separation of just 1.56 mm. Also the radiation patterns are improved due to the mutual coupling reduction.