A circularly polarized dielectric resonator antenna excited by an asymmetrical U-slot with a backing cavity

A cavity-backed circularly polarized dielectric resonator antenna (DRA) excited by an asymmetrical U-slot is investigated theoretically and experimentally. The finite-difference time-domain method using nonuniform orthogonal grids is employed to study the new configuration, with the excitation modeled by an independent resistive voltage source. The return loss, input impedance, axial ratio, and radiation pattern of the antenna are studied. Reasonable agreement between theory and experiment is obtained.