A Circularly Polarized Millimeter-Wave Antenna with High Radiation Efficiency

A circularly polarized antenna with high radiation efficiency is proposed in this paper, which is based on multilayer PCB design and suitable for 28GHz millimeter wave band. The proposed antenna element is composed of four groups of monopole antennas that distributed in symmetrical structure. Each group of monopole antenna includes a feeding structure, a primary radiation sheet and a parasitic radiation sheet. The four groups of monopole antennas are successively fed with equal amplitude and 90° phase difference, then form circularly polarized antenna. Integrated with feed network and coaxial cable-like structure, the proposed antenna can cover the bandwidth of 26.5~29.5GHz with VSWR<1.2, AR<1.5dB and average radiation efficiency higher than 90%.