Wideband Decoupled 8-Element MIMO Mobile Phone Antenna for Sub-6GHz 5G NR Bands

A broadband decoupled dual antenna pair suitable for sub-6G mobile terminal application is proposed and designed. The multiple input multiple output (MIMO) antenna pair is arranged on the metal frame of the mobile phone, with two antenna pairs on each metal frame. The slotted antenna element structure and defect ground decoupling structure are used to achieve wide band and high isolation. Based on the decoupled antenna pair, an eight-element MIMO antenna is designed. Similarly, the coupling between antenna pairs is effectively reduced by etching the decoupled defect structure of a zigzag shape on the system surface. The prototype of the antenna array is successfully fabricated and tested. Simulation and experimental results show that the proposed eight-element MIMO antenna can fully cover the n77/n78/n79 band of 5G New Radio and 5 GHz band of WLAN. The overall efficiency of the antenna is 50%-75%, the envelope correlation coefficient (ECC) is below 0.08, and the isolation between any two ports is better than 11 dB.