Dual-Wideband Dual-Polarized Dipole Antenna With T-Shaped Slots and Stable Radiation Pattern

Abstract

A dual-wideband dual-polarized dipole antenna for base-station applications is proposed. This antenna consists of a pair of crossed dipoles, a circular director, and a metallic reflector. The crossed dipoles are fed by two 50 Ω coaxial cables to achieve ±45° polarized radiation over a wide frequency band, while four T-shaped slots are cut in the dipole arms to produce two wide operating bands. The circular director is employed and located above the dipoles to enhance the impedance matching and further stabilize the radiation pattern at the higher frequency band. To further stabilize the pattern, four baffles are added along the edge of a square reflector. Measured results demonstrate that this antenna has two broad bandwidths of 47.8% (1.67–2.72 GHz) and 16.6% (3.3–3.9 GHz) for VSWR < 1.5 at the lower and higher frequency bands, respectively. Stable half-power beamwidths of 67.5°±8.5° for the lower frequency band and 64°±5° for the higher frequency band are obtained. The measured gains are stabilized at 8.1±0.5 dBi for the lower band and 8.35±0.25 dBi for the higher band. This antenna is potentially attractive for mobile communications.