Dual-Band Aperture-Shared Base Station Antenna Based on Broadband Electromagnetic Transparent Structure

This paper introduces a dual-band aperture-shared antenna array with broadband electromagnetic (EM) transparency for base stations. The antenna array integrates a low-band (LB) antenna with a 4×4 high-band (HB) antenna array. Positioned directly above the HB antenna array, the LB antenna and both of the antennas share a radiation aperture. The periodic metal strips are loaded on both sides of the LB antenna’s dipole to achieve EM transparency for the HB antenna and to mitigate the blockage effects on the HB antenna’s radiation performance. To validate its EM transparency characteristics, a dual-band aperture-shared base station antenna array was fabricated and tested, operating at a frequency range of 0.76–0.96 GHz (VSWR<1.8, 23.3%) and 3.2– 5.0 GHz (VSWR<1.8, 43.9%). The measurement results show that by loading the EM transparency structure, the HB antenna’s radiation pattern is restored, and the gain fluctuation in the normal radiation direction is less than 0.8 dBi, verifying the broadband EM transparency characteristics of the structure. Thereby, the proposed dual-band aperture-shared base station antenna array offers an effective solution for integrating 5G with earlier communication frequency bands.