Sub-6 GHz Dual-Band 8 × 8 MIMO Antenna for 5G Smartphones

In this letter, a dual-band 8 × 8 multiple-input-multiple-output (MIMO) antenna that operates in the sub-6 GHz spectrum for future 5G MIMO smartphone applications is presented. The design consists of a fully grounded plane with closely spaced orthogonal pairs of antennas placed symmetrically along the long edges and on the corners of the smartphone. The orthogonal pairs are connected by a 7.8 mm short neutral line for mutual coupling reduction at both bands. Each antenna element consists of a folded monopole with dimensions 17.85 × 5 mm² and can operate in 3100-3850 MHz for the low band and 4800-6000 MHz for the high band (|S₁₁| <; 10 dB). The fabricated antenna prototype is tested and offers good performance in terms of envelope correlation coefficient (ECC), mean effective gain (MEG), total efficiency, and channel capacity. Finally, the user effects on the antenna and the specific absorption rate (SAR) are also presented.