Highly Compact Array MIMO Module for EMI Immune 5G Wireless Communications

A highly compact MIMO array antenna module with electromagnetic interference (EMI) immune capability is designed, implemented, and characterized for secure 5 GHz Wi-Fi applications. The size of the array antenna is greatly reduced by shrinking the gap between array elements to 2 mm (0.033λ_0). The mutual coupling between array elements is effectively suppressed by adding diagonally placed meander-line (ML) ring resonators under each element without degrading antenna gain and directivity performance. Compared with a conventional 2 x 2 array antenna module, the demonstrated 2 x 2 one shows 65% area reduction. The resonant frequency of the fabricated structure matches well with the target frequency. The feeding locations of the patch elements are optimized for a symmetric design. A mutual coupling reduction of more than 13 dB has been demonstrated.