A base station antenna element with simple structure but excellent performance

A ±45° dual-polarized concentrically arranged dipole antenna is proposed for base station applications. The simple, robust antenna consists of four simple dipoles arranged in a square above a flat reflector. Two specially designed feeding networks for the two polarizations are proposed to simultaneously excite the four dipoles. Without shaping the reflector, the combination of four dipoles provides a stable radiation pattern across a wide bandwidth. Measured results show that the proposed antenna has an input reflection coefficient ≤-14 dB from 1.71 to 2.71 GHz for both polarizations. Across this wide bandwidth (45.2%), the half-power-beamwidths (HPBWs) of the two polarizations remain very stable in the range from 60.5° to 69.5°. High port-to-port isolation ≥ 30 dB and low cross-polarization level ≤-20 dB are achieved over the entire operating band.