Dual-Polarized Dipole Array Antenna with Tilt Angle for Sub-6 GHz Base Stations

In this paper, a dual-polarized dipole array antenna is proposed. The unit antenna is designed with two pairs of crossed ring dipoles as the antenna radiators, which resonate at the frequency band (n78, 3300 ~ 3800 MHz). A balun circuit use to improve the impedance mismatch and enhance the antenna’s operating bandwidth. Furthermore, to meet the electrical down-tilt range of 0 to 10 degrees for the base station, a series-connected one-to-four power divider in the feed network is adopted. At the output end of the power divider, we add phase delay lines to combine the phase shifting network with the power divider. Each output port has a phase difference of 45 degrees, resulting in beam steering effects for the antenna array. According to the actual measurement results, the operating bandwidth of this array antenna covers 2820.5 to 4357.5 MHz, with a dual-notch isolation of 20 dB or more, electrical down-tilt of 10 degrees and an antenna gain of approximately 8 dBi.