Design of a Dual-Polarized Base Station Antenna for Mobile Communication

Abstract

In this project, a dual-polarized unidirectional base station antenna for mobile communication is proposed. This antenna employs the geometry of magneto-electric dipole to achieve wide bandwidth and low back lobe across the operating frequency. Metal strips are introduced for both feeding and matching. A rectangular cavity is used to obtain better isolation, and high gain with low back-lobe level. Simulation results by HFSS show an operating frequency from 1.7GHz to 2.7GHz for VSWR less than 1.5, an average gain of 9.8dBi with 1.85dBi variation, and isolation between two ports larger than 30dB. The front-to-back ratio is less than -17dB at 2.7GHz and gets smaller to -28dB at 1.7GHz. In E-plane, the cross-polarization is less than -30dB over the whole operating frequency. In H-plane, the cross-polarization is -17.4dB at 1.7GHz and decreases to approximately -30dB at 2.7GHz. In addition, this antenna with direct feeds is DC grounded and satisfies the requirement imposed on outdoor application.