Improving Isolation in a Wideband Microstrip MIMO Antenna for 5G Applications

This letter presents a 2× 2 microstrip patch MIMO antenna on a suspended substrate optimized for the n78 5G band with enhanced isolation performance. Several decoupling methods, including grounding metallic strips between patches, placing a metallic cross -shaped wall under the substrate, and truncating patch corners, were analyzed by simulations to assess their effectiveness. Key geometric parameters affecting isolation were studied using their equivalent circuits before integrating all these methods into the proposed MIMO array. This array achieves a 6.67 dBi peak gain, 26.46% impedance bandwidth, and 17.2% decoupling bandwidth for isolation better than 20 dB. This design offers an excellent channel capacity loss (CCL), making it suitable for 5G base station antennas.