A Compact Wideband Dual-Polarized Base Station Antenna Using Asymmetric Dipole

Abstract

A compact wideband dual-polarized antenna for base station application is proposed. The antenna element consists of a main radiator, two baluns, and a reflector. Two methods are used to enhance bandwidth and improve the port-to-port isolation. Firstly, by integrating the parasitic elements to traditional dipoles, new resonant modes are introduced to realize broadband, which can be controlled flexibly. Subsequently, part of the parasitic elements is removed to form asymmetric dipoles. Due to the asymmetry construction of the design, the polarization isolation of the antenna achieves more than 30 dB in the whole working band with stable radiation patterns. In addition, the specially designed parasitic elements achieve enhanced bandwidth without increasing the size of the radiator. The Simulation and measurement results show that the antenna has an impedance bandwidth of 32.7% (690-960 MHz). Moreover, a stable half-power beamwidth (HPBW) of 68°±5° and a high gain of 8.5±0.3 dBi is achieved. To verify the performance of the antenna, a compact high-gain base station array was designed and manufactured. The good performance of the proposed antenna makes it a promising candidate for 4G/5G base station application.