A Compact MIMO Antenna and Its Time Reversal Super-Resolution Focusing

A compact four-element planar MIMO antenna with microstructures is proposed. The distance between adjacent elements is only ~0.3λ
₀
. Isolation structures are introduced to reduce the mutual coupling. The simulated impedance matching, isolation and envelope correlation coefficient (ECC) performances of the antenna are presented. By using a Time Reversal electromagnetic wave simulation, the antenna demonstrates super-resolution focusing characteristics. The results show that the super-resolution focusing is closely related to the microstructures around the antenna.