Compact Ultra-Wide Band MIMO Antenna System for Lower 5G Bands

This paper presents a novel compact 2 x 2 planar MIMO antenna system with ultra-wide band capability. Antenna system is specifically designed to target lower 5th generation operating bands ranging from 2 GHz to 12 GHz. This band also covers the IEEE 802.11 a/b/g/n/ac. The antenna array geometry has been simulated using CST MWS. The design is extremely miniaturized with total structure size of 13 x 25 x 0.254 mm(3). The simulated and measured results have been presented. Measured and simulated return loss values for designed antenna are less than -10 dB over the operating band and lowest values of -35 dB and -32.5 dB can been seen at 5.2 GHz and 9.2 GHz, respectively, whereas at the center frequency the return loss is -25.2 dB. The mutual coupling between both elements is less than -20 dB over the transmission bandwidth. Simulated and measured radiation patterns in E and H planes at center frequency show nearly isotropic far fields. The maximum gain is measured as 4.8 dB. Promising results of Envelope Correlation Coefficient and gain diversity of the design have been achieved. Simulated and measured results are found in good agreement. The fractional bandwidth of antenna is measured as 143.2% which satisfies its ultra-wide band response.