Dual-Band Dual-Polarized Shared-Aperture Antenna Based on the Transparent Structure with Frequency Selection Characteristics

A dual-band dual-polarized shared-aperture antenna for base station application is proposed. It includes a low-band (LB) antenna and a 2 x 2 high-band (HB) antenna array, which can cover the frequency bands of 1.8-2.65 GHz and 3.3-3.8 GHz. The LB antenna and HB antenna share the same reflector. The reflector is located at the bottom. The LB antenna is placed above the HB antenna array. As a result, LB antenna has shielding effect on HB antenna. In order to enable two antennas to work in the same aperture at the same time, the shielding effect of LB antenna on HB antenna must be eliminated. Based on the principle of frequency selection surface, the LB antenna proposed in this paper is a double-ring structure with frequency selection characteristics. In other words, the radiator of LB antenna exhibits electromagnetic transparency in HB. In this way, the LB antenna can work normally in LB without affecting the radiation performance of the HB antenna. The simulated results verify that the proposed shared-aperture antenna can achieve stable radiation performance in LB and HB.