A Broadband Dual-Polarized Planar Antenna for 2G/3G/LTE Base Stations

Abstract

A broadband dual-polarized planar antenna is proposed for 2G/3G/LTE base stations. The dual-polarized antenna is composed of two perpendicularly crossed bow-tie dipoles. Each bow-tie dipole is excited by a microstrip stub that is directly fed by a coaxial line, making the dual-polarized antenna full planar. Due to the coupling between two crossed bow-tie dipoles, a broad bandwidth is achieved. It is shown that the dual-polarized antenna has a bandwidth of 45% (1.7-2.7 GHz) for return loss >15 dB with an isolation of higher than 30 dB between two polarization input ports. The dual-polarized antenna has a half-power beam width (HPBW) of around 65 ° and an average gain of 8.5 dBi for slant ±45° polarizations. An 8-element dual-polarized planar antenna array is developed for base station applications. A bandwidth of 56% (1.63-2.9 GHz) is obtained for the antenna array. The antenna gain of the array is about 16 dBi and the HPBW is 65±8° for each polarization.