A novel four-polarization MIMO array with combined bridge

In this communication, a novel four-polarization MIMO array with combined bridge is proposed. The feed network of the MIMO array is composed of branch line coupler, Sheffman phase shifter, Wilkinson power divider, U-shaped branch and Π Type attenuator. By feeding different input ports, the antenna 0°/90°/±45°polarization can be achieved. Through simulation, the VSWR of antenna array is less than 1.2 and the isolation between ports is less than -25dB in the 1.785-1.805GHz frequency band. The design can realize four-polarization without bias circuit and lumped elements, and has the advantages of simple circuit, high port isolation and good port impedance matching.