Metasurface-driven Improvement in MIMO Antenna Performance by Addressing Mutual Coupling

In this paper, a metasurface is proposed as an effective solution to enhance the performance of MIMO antennas by reducing mutual coupling. This reduction is attributed to the metasurface's negative permeability at the resonant frequency, which helps to block waves propagating between the two adjacent structures. The designed metasurface consists of a 2D array of omega-shaped resonators placed over two linearly polarized patch antennas. Measurement results show a 15 dB reduction in coupling when the metasurface is positioned 0.14λ0 above two closely spaced antennas separated by 0.06λ0 at a resonant frequency of 2.85 GHz. Additionally, improvements in other characteristics of the whole structure, such as gain and radiation efficiency, were also observed. Such an achievement has not been reported in the literature on previous metasurface-based decoupling methods. This technique can be useful for massive multiple input multiple output (mMIMO) systems for wireless communications.