Side-Edge Frame Coupled-Fed Printed Eight-Port MIMO Antenna Array for Sub-6 GHz 5G Smartphone Applications

A compact 8-port coupled-fed multiple-input multiple-output (MIMO) array antenna for future sub-6 GHz 5G smartphone applications is presented in this paper. The proposed MIMO array consists of eight coupled-fed inverted-L antenna structures with the compact size of 11.7 × 6 mm2 (00.1365λ × 0.07λ), which are embedded in the inner surface of the two long side frames of the 5G smartphone. From the simulated results, the impedance bandwidth (S11<-6dB) of the proposed MIMO array antenna covers the LTE 42 (3.4-3.6 GHz) operating band. The typical averaged antenna efficiencies of 79% (Ant1, Ant4, Ant5, and Ant8) and 77% (Ant2, Ant3, Ant6, and Ant7), and peak gains 2.4 dB (Ant1-Ant8) are observed. The isolation between any two antennas is better than 17 dB. The calculated ECCs and diversity gain (DG) is less than 0.02 and 10 respectively, which shows the proposed antenna is a promising candidate for MIMO diversity performance for sub-6 GHz 5G smartphone applications.