Design of a Compact Planar UWB MIMO Antenna with Enhanced Isolation for Diversity Applications

This paper presents the design and simulation of a 2×2 Koch fractal antenna array with metamaterial in HFSS for UWB applications. The antenna operates from 3 GHz to 13 GHz with a return loss below -10 dB and resonance at 3.8 GHz and 12 GHz. Mutual coupling is reduced below -40 dB (simulated) and -50 dB (measured). The radiation patterns show close agreement, with a maximum variation of 0.05–0.1 dB. The multiplexing efficiency exceeds 60%, and the ECC remains below 0.02, confirming excellent isolation and diversity, making it suitable for high performance UWB systems.