Performance Comparison of 2x2 MIMO Antennas with Metasurface Structure for Mitigating Mutual Coupling in 5G MIMO Systems

This paper presents a comparative study of different metasurface structures in a $2 \times 2$ MIMO antenna system. Three unit cells were designed and analyzed using dispersion diagram analysis to achieve resonance of surface wave propagation at 3.5 GHz. The unit cells were arranged in an array to observe their effect on reducing mutual coupling. Each unit cell demonstrated varying levels of optimal mutual coupling reduction at different antenna spacings. All three unit cells achieved mutual coupling reductions of up to 40 dB, with the closest antenna spacing at 1.06 wavelengths. Other performance aspects, such as the Envelope Correlation Coefficient and diversity gain, were also studied.