Millimeter-Wave MIMO Antenna With Decoupling Structures for Isolation Enhancement

MIMO antenna of 4 elements with decoupling structures is presented for millimeter-wave applications. The antenna consists of radiating elements and decoupling structures such as defective ground plane and metasurfaces individually or combined. First, an optimized defected ground surface (DGS) is introduced to improve the isolation over 60-75 GHz (22%) bandwidth with an inner edge separation of 0.55 mm (0.13 lambda(0)) at 70 GHz. Furthermore, metasurface realized by split ring resonators at 0.6 lambda(0) from the antenna elements improved the isolation of the 4 elements by a maximum of 25 dB. The proposed antenna's gain, efficiency, and surface currents are compared to the initial 4 elements to verify the proposed decoupling technique for MIMO applications.