Design of Wideband Metal-Frame MIMO Antenna Based on Mode Control for 5G Smartphones

This work presents a 5G broadband MIMO antenna array applied to the metal frame of smartphones. Based on the mode regulation, the ratio of fundamental mode and high mode frequencies is reduced to achieve 3.3-6.0 GHz broadband coverage. At the same time, two low frequency antenna units are designed for multiplexing with decoupled structure, which can cover PCS(1850- 1990 MHz), UMTS(1920-2170 MHz), LTE2300(2300-2400 MHz) and LTE2500 frequency band (25000–2690 MHz), respectively. The low frequency antennas not only participate in radiation, but also act as a decoupled structure for 5G broadband antennas to improve space utilization. Experiment results show that the designed MIMO antenna array has good performance in the operating band of 3.3-6.0 GHz with ECC less than 0.04 and efficiency up to 80%.