Planar Wideband Circularly Polarized Antenna for 5G Millimeter-Wave Applications

This paper presents a simple structure millimeter wave circular polarization slot antenna. The slot antenna and the feed structure are printed on the positive and negative two planes of the same plate, which is the structure of a single layer of dielectric substrate and two layers of metal. Under the excitation of microstrip coupling feed, two orthogonal electric fields with orthogonal phase difference are excited at the edge of the rectangular slot with angle etched on the floor to realize circularly polarized radiation. To realize the circularly polarized radiation performance of the broad band millimeter wave, we broaden the axial ratio (AR) bandwidth by removing two angles to correct the floor shape and introducing an L-shaped slot with two angular symmetry. The antenna structure design, principle analysis and key parameters analysis. Simulation results show that the 3 dB AR bandwidth is 23.91-50.15 GHz and the 10 dB impedance bandwidth is 29.45-58.22 GHz, realizing a broadband circular polarization in the range of 29.45-50.15 GHz.