A Shared-Aperture Dielectric Resonator Antenna with Linear and Circular Polarization Diversity

This paper presents a novel shared-aperture cylindrical Dielectric Resonator Antenna (DRA) with linear and circular polarization diversity. A modified orthogonal coupler is designed to excite the DRA with the linear-polarization $\text{TM}_{01\delta}$ mode at 4.6GHz by feeding Port 1, and higher modes at 5.0 and 5.7 GHz by feeding Port 2. These modes operate at dual frequencies but sharing the same aperture. Meanwhile, the circular-polarization is obtained by feeding Port 3 or Port 4 with orthogonal circular ring microstrip coupler, which provides equal amplitude and ±90° phase difference. The proposed shared-aperture DRA is verified by fabrication and measurement for its diversities on frequency and polarization. It could be a promising candidate for sub-6G indoor base station antenna.