Wideband Highly Efficient Eight Element MIMO Antenna Using Differential Fed Open End Slot for Sub-7 GHz 5G Mobile Handset Applications

A new method of wideband impedance matching for a massive fifth-generation (5G) Multiple Input Multiple Output (MIMO) antenna is presented in this paper. The technique uses a simple differential-fed open-end slot antenna (OESA) as MIMO elements. VSWR 3:1 bandwidth (BW) of the MIMO antenna covers the 5G new radio bands of N77, N78, N79, and LTE-46 within the sub-7 GHz. The measured return loss BW of the array is obtained over 3.29-6.61 GHz (67.1 %). The minimum isolation between adjacent antennas is 16.6 dB. The MIMO shows uniform radiation and an average efficiency of > 70 % within the band of interest. The MIMO is evident to have a low envelope correlation coefficient and a high channel capacity with values of 0.057 and 40.94 bps/Hz. The specific absorption rate is analyzed for human head phantom and single and dual hand-mode operations to show the radiation effect on the body tissue.