Mutual-Coupling Reduction Using Metasurface Corrugations for 28 GHz MIMO Applications

An efficient method for improving the mutual coupling between two antipodal Fermi-based tapered slot antennas is presented. This is achieved by using metamaterial-based corrugations, acting as a metasurface shield, etched on edge side of the substrate. An array of split-ring resonator unit cells is incorporated into the design to suppress leakage from the side walls and to improve the isolation. The effect of metasurface corrugations results in a mutual coupling improvement of 12-15 dB over a frequency band from 27 to 32 GHz. Moreover, the radiation characteristic of the proposed antenna is not affected, leading to a higher gain and improved total efficiency with low mutual coupling. The proposed antenna is a suitable candidate for 28 GHz multiple-input-multiple-output (MIMO) systems. The measured isolation of the prototype antenna varies from -37.1 to -49.8 dB along with a measured gain of 16.13-17.92 dB over an operating frequency band from 27 to 32 GHz.