Compact multi-functional MIMO Antenna with SRR-Enhanced Isolation for B5G/6G Systems

This study presents a compact and cost-effective antenna for Beyond 5G (B5G) and 6G systems. The prototype, featuring a rectangular patch with a full ground plane on an FR4-epoxy substrate, performs very well at 26 GHz, achieving over 80% efficiency, a peak gain of 7 dBi, and an S11 below −45 dB. A two-element MIMO configuration was then developed. To reduce the strong coupling that usually occurs between closely spaced elements, linear split-ring resonators were added between the radiating elements. This solution effectively reduced interference while maintaining high antenna performance, improving isolation to −40 dB across the working band. The proposed MIMO system also shows excellent metrics: the envelope correlation coefficient (ECC) is around 0.001, the diversity gain (DG) reaches 9.9 dB, the channel capacity loss (CCL) is about 0.002 bits/Hz/s, and the total active reflection coefficient (TARC) is close to 0.006. Overall, the design provides a simple and effective approach to building compact, high-performance MIMO antennas, making it well suited for next-generation B5G and 6G applications.