Millimetre-Wave MIMO Array of a Compact Grid Antenna for 5G Wireless Networks and Beyond

Abstract

This paper presents a 4-element multiple-input-multiple-output (MIMO) configuration of planar and compact two-dimensional (2D) grid antennas. The proposed grid is a 2D array of thirteen circular patches each with a radius of 0.175$\lambda _{\mathbf{o}}$, having a single feed point. Measured results of the single-element microstrip-fed grid-array antenna show a 6 GHz bandwidth in the range of 27-33 GHz. The realized gain is above 9 dBi in almost the whole range with a peak gain of 11.57 dBi at 29 GHz. The numerically calculated antenna efficiency is above 80%. The transmission characteristics of the 4-element MIMO array are below –27 dB that indicates low mutual coupling and high isolation. These high-performance aspects of the proposed millimetre-wave (mm-wave) MIMO antenna array validate its potential for the 5$^{\mathbf{th}}$ generation (5G) cellular devices especially in indoor base-stations.