Decoupling of Dual-Polarized 5G Base Station Antenna Using Back Cavities

A dual-polarization base station antenna array based on a back cavity and metal plate decoupling structure is introduced. There are two crossed dipoles on the upper surface of the horizontal dielectric plate to achieve ±45° polarizations. Each balun has an FR4 vertical substrate with Γ feeders transformer and slotted metal ground on the back. This antenna operates in C band (3.3-3.8 GHz) with VSWR < 1.5, the isolation between the two polarized ports is better than 27 dB. With the decoupling structure, the co-polarized coupling between two elements is improved by at least 9.5 dB, and the cross-polarized coupling between two elements is improved by up to 2 dB, and the gain is increased by 0.2 dBi in the working frequency band.