A broadband dual-polarized antenna with filtering function for base stations

In this paper, a broadband dipole antenna with filtering function is proposed. The proposed antenna as a whole comprises a reflector, coaxial cables, a main radiator, and a cross-center structure. First, two orthogonal dipoles are used as the main radiator and form dual-polarization. By adding Y-shaped branches and a cross-center structure, the base station antenna realizes the filtering function and expands bandwidth. The antenna has filtering function on both sides of the operating frequency band, and the out-of-band radiation suppression can be 16 dB at the upper band. The radiation null can be controlled independently by the additional structure. And the parasitic structure has little effect on the realized gain in the operating frequency band. The measurement results show that the relative operating bandwidth of the proposed antenna exceeds 54%, and the isolation between ports is greater than 27 dB. In the operating frequency band, the realized gain is relatively flat, and the HPBW is in the range of 67.3 degrees +/- 2.6 degrees.