A High Gain Array Based Millimeter Wave MIMO Antenna with Improved Isolation and Decorrelated Fields

A high gain antenna system with improved isolation for 5G applications is proposed and investigated. The radiating structure consists of a combination of multiple strips to make the proposed design resonate within the desired frequency band of 28 GHz being of major interest for 5G applications. The antenna element provides 684 MHz operating bandwidth and a peak gain of 5.85 dB with a radiation efficiency of 70.9%. Using four antenna elements in an antenna array, connected with a T-shaped feeding network, provides a 12.5 dB peak gain and radiation efficiency of 91.5%. The efficiency improvement of almost 20% is achieved by the reduction of the mutual coupling between antenna elements in the array configuration. This also leads to a low side lobe level (SLL) and an improvement in the bandwidth to 1.53 GHz. Furthermore, the four-port multiple-input-multiple-output (MIMO) configuration is obtained using the proposed array configuration which gives an optimum gain, uncorrelated fields, reasonable bandwidth, and isolation of more than 30 dB with a satisfactory MIMO performance metrics. Due to the abovementioned promising features of the proposed antenna design, it can be very useful for important 5G applications.