A Wideband Dual-Polarized Filtering Antenna for Base Station Applications

A wideband dual-polarized filtering antenna is presented in this paper for base station applications. This antenna is composed of the center driven crossed-dipoles and four parasitic stepped split-loop. It is investigated that the center dipole arm can introduce the first radiation null at the lower band-edge, and the width of the stepped split-loop can affect the second radiation null at the upper band-edge. Therefore, by controlling these two parameters, a wideband dual-polarized antenna with quasi-elliptic filtering response can be realized. Finally, this antenna was designed, fabricated, and measured for performance verification. The measured results prove that the presented antenna can have a wide impedance bandwidth covering 1.7-2.9 GHz, and high suppressions of 33.8 db and 20.6 db over 0.6-1 GHz and 3.3-5 GHz.