Broadband dual‐polarized crossed‐dipole antenna with tapered integrated balun for base‐station applications

Abstract

A ± 45° dual-polarized dipole antenna with low profile and stable radiation pattern over a wide operating band for base station is proposed. The antenna is formed by two polygon-shaped dipoles and a shaped metallic reflector. Two baluns with tapered structure are used to excite the dipoles for dual-polarized radiation and enhancing the impedance matching and bandwidth, while the shaped-reflector is used to obtain stable radiation pattern in the horizontal plane during a wide frequency band. The design principles of crossed dipoles, baluns and reflector is described in detail. The proposed antenna achieves wide impedance bandwidth of 67% for VSWR<1.5, and high-isolation better than 31 dB over the operating band. In addition, the 3 dB beamwidth in the horizontal plane of the antenna is stabilized within the range of 66.3° ± 2.8°. These performances make the presented antenna applicable for mobile communications.