Low Mutual Coupling for DRA-based Massive MIMO Antenna Arrays by Using Decoupling Cavity

Mutual decoupling in massive MIMO (Multiple-Input Multiple-Output) antenna systems is crucial for enhancing performance, particularly in advanced communication applications of the next generation. In this study, we propose a dielectric resonator antenna (DRA)-based massive MIMO antenna that incorporates decoupling cavities (DC) to improve isolation between elements, ensuring efficient operation at the 5 GHz frequency band. The proposed design utilizes a cylindrical DRA-based massive MIMO antenna, combined with a seamlessly integrated DC structure composed of three layered levels, positioned above the reference massive MIMO antenna array. The DC is made of an FR-4 board, with air cavities engraved into it. Simulation results demonstrate that integrating a DRA-based mMIMO antenna with DC significantly reduces coupling between array elements, from -17 dB to -30" " dB, increases the bandwidth to 1200" " MHz, improves the envelope correlation coefficient (ECC) and diversity gain, and enhances the radiation pattern in the E-plane.