Mutual Coupling Reduction in a DGS-Incorporated Millimeter-Wave MIMO Antenna Array

This paper presents a T- and E-shaped defected ground surface (DGS) to reduce the mutual coupling in a tightly spaced MIMO antenna array in the millimeter-wave (MMW) frequency range. By carefully optimizing the dimensions and positions of the slots on the ground plane, a 50 dB maximum mutual coupling reduction is achieved over the 62-77 GHz bandwidth (21.6 %), with an edge-to-edge spacing of 0.55 mm (0.13λ), where λ is the free-space wavelength, at the center frequency of 70 GHz. The carefully etched ground plane also improved the bandwidth, especially between the 60-70 GHz band, with good radiation properties. These results make the proposed tightly spaced, highly isolated MMW antenna array a good candidate for MMW V-band applications.