Dual‐polarized filtering antenna with harmonic suppression for base station applications

Abstract

AbstractA dual‐polarized filtering antenna (DPFA) with high‐order harmonics suppression for 690‐960 MHz based station applications is proposed in this letter. The proposed DPFA is obtained by integrating a miniaturized lowpass filter with a ±45° dual‐polarized antenna (DPA) which made by two crossed dipoles. With the miniaturized lowpass filter, harmonic suppression is easily achieved by the proposed DPFA without increase its size. The experimental results which agree with the computer simulations show that wide impedance bandwidth (|S11| < −15 dB) of 43.2% (690‐1070 MHz) and harmonic suppression frequency up to 4.5 GHz are realized. In the operating frequency band (690‐960 MHz), port‐to‐port isolation of more than 35 dB, cross‐polarization discrimination of more than 27 dB, 3‐dB beamwidth of 68.8° ± 2.1°, efficiency of more than 82%, and stable gain of 8.2 ± 0.5 dBi are obtained by the proposed DPFA. In addition, radiation suppression of more than 18 dB in the interference bands (1690‐2690 MHz and 3300‐3800 MHz) is obtained.