Compact Wideband Metal‐Frame 8‐Port MIMO Antenna Based on Shared Radiator for 5G Mobile Phones

ABSTRACT

A compact wideband 8‐port multiple‐input multiple‐output (MIMO) antenna designed for fifth‐generation (5G) mobile applications is proposed. This antenna features a shared radiator and is compatible with metal‐frames. Its dimensions are 150 × 75 × 7 mm, and it consists of four dual‐port antenna pairs, forming an 8‐port MIMO configuration. The shared radiator design enables each antenna pair to occupy only 20 × 7 mm, with a substrate thickness of 0.8 mm, ensuring sufficient space for other components. To achieve full coverage of the 5G N77/N78/N79 bands (3.3–5.0 GHz), an impedance matching network with lumped elements is incorporated to improve impedance matching. The simulation results show that the bandwidth of −6 dB ranges from 3.29 to 5.30 GHz, corresponding to a fractional bandwidth of 47%. Decoupling capacitors are loaded at the center of each antenna pair to improve isolation, achieving an isolation level better than –11 dB. The total efficiency of the proposed antenna within the operating band reaches approximately 85%. Simulation results also show that the antenna's performance remains basically unchanged when handheld. Measurement results confirm that the S‐parameters and radiation performance agree well with the simulation results.