A compact wideband circularly polarized MIMO antenna with polarization diversity

The present work describes a two-element MIMO (Multiple Input Multiple Output) antenna with circular polarization, which operates in the sub6 GHz 5G frequency range. The antenna design consists of two printed monopole antennas which are arranged in the mirror position with a spacing distance of 0.057 λ0 at the lowest operating frequency (where λ0 represents free space wavelength). A parasitic element has been deployed to achieve the circular polarization. A flat reflector is installed in the back of the antenna to improve the antenna gain in the boresight direction. The 10dB impedance bandwidth overlapped with 3dB axial ratio bandwidth is 38.1%, ranging from 3.4 to 5 GHz.