Dual-Polarized Dipole Antenna With Dual-Band Spatial Filtering Response for Aperture-Shared Triband Base Station Array Application

This letter presents a lower band (LB) dipole antenna with a dual-band spatial filtering response for base station applications. The proposed LB dipole antenna has four square loop arms, each square loop arm is integrated by two types of split-ring structures. Each split-ring structure can be used to form a spatial bandpass response at one upper band. As a result, the LB antenna can realize electromagnetic transparent property at two upper bands while maintaining the performance at LB. For demonstration, a triband aperture-shared antenna array, operating at the LB of 0.69–0.96 GHz, middle band (MB) of 1.7–2.7 GHz, and the higher band (HB) of 3.3–3.8 GHz, is fabricated and measured. The simulated and measured results show that the S-parameters and radiation patterns of the HB and MB antennas change slightly compared to those of the subarray alone, verifying the effectiveness of the design method. The proposed LB antenna is suitable for compact multiband aperture-shared arrays, especially for 2G/3G/4G and 5G integration base station arrays.