Circularly Polarized Microstrip/Elliptical Dielectric Ring Resonator Antenna for Millimeter-Wave Applications

A new single-element circularly polarized antenna for millimeter-wave applications is presented in this letter. A simple hybrid microstrip/elliptical dielectric ring resonator configuration is used to achieve a relatively high antenna gain. A reversed T-shaped coupling slot generates the circular polarization. The ring-shaped dielectric resonator is used to increase the gain and fine-tune the axial ratio (AR) bandwidth. Measurements show that an impedance bandwidth of 12% and a considerably wide axial ratio bandwidth (10%) are possible. The measured gain is maintained over 9 dB for a large portion of the operational bandwidth.