A Decoupling Scheme for Closely Spaced Microstrip Patch Antenna

This article introduces a simple decoupling method aimed at achieving high isolation among closely spaced antennas. The study focuses on evaluating the impact of the gap between antenna elements on coupling for an H-plane array antenna. The decoupling structure comprises transmission line resonators and vias, which effectively mitigate coupling when two antennas are positioned with a minimal 2 mm edge-to-edge separation. The inclusion of resonators effectively diminishes the coupling between these antennas. To affirm the practical utility of this configuration, the design is implemented and rigorously validated through measurements. The proposed structure demonstrates an impressive 40 dB isolation with a gain of 2.3 dBi. Furthermore, a three-element array is examined to confirm the effectiveness of this proposed approach for linear element arrays.