Eight-Port Modified E-Slot MIMO Antenna Array with Enhanced Isolation for 5G Mobile Phone

An eight-element antenna system operating at sub 6 GHz is presented in this work for a future multiple-input multiple-output (MIMO) system based on a modified E-slot on the ground. The modified E-slot significantly lowers the coupling among the antenna components by suppressing the ground current effect. The design concept is validated by accurately measuring and carefully fabricating an eight-element MIMO antenna. The experimentation yields higher element isolation greater than -21 dB in the 3.5 GHz band and the desired band is achieved at -6 dB impedance bandwidth. The E-shape slot occupies an area of 17.8 mm x 5.6 mm designed on an FR-4 substrate with dimensions of 150 mm x 75 mm x 0.8 mm. We fed the I-antenna element with an L-shape micro-strip feedline, the size of the I-antenna is 20.4 x 5.2 mm(2), which operates in the (3.4-3.65 GHz) band. Moreover, our method obtained an envelope correlation coefficient (ECC) of <0.01 and an ergodic channel capacity of 43.50 bps/Hz. The ECC and ergodic channel capacity are important metrics for evaluating MIMO system performance. Results indicate that the proposed antenna system is a good option to be used in 5G mobile phone applications.