MIMO Antenna With Compact Decoupled Antenna Pairs for 5G Mobile Terminals

In this letter, a compact self-decoupled antenna structure is proposed for the fifth-generation multiple-input--multiple-output (MIMO) operation in mobile terminals. The antenna structure consists of two adjacent antenna elements, which are placed very close (1.2 mm or 0.014λ) to each other and located on the same side of the system ground plane. By sharing one common grounding branch for the two adjacent antenna elements, a compact self-decoupled antenna pair can be obtained. The MIMO antenna system is optimized to operate in the 3.5 GHz (3.4-3.6 GHz) band with isolation better than -17 dB. An antenna prototype is fabricated, and good agreement between simulation and measurement is obtained.