Design of a Circularly Polarized Dielectric Resonator Antenna with Wide Bandwidth and Low Axial Ratio Values

摘要： A circularly polarized (CP) dielectric resonator antenna (DRA) with wide bandwidth and low axial ratio (AR) values is presented in this communication. The antenna consists of a stacked DRA, and it is fed by a substrate integrated waveguide (SIW) coupling slot from the bottom. The stacked DRA structure, with high permittivity dielectric strips layered on low permittivity substrate, is adopted for bandwidth and gain benefits. Here, a pair of dielectric strips rather than a single one is placed above the coupling slot with 45° inclination for generating good CP radiation, and it is elaborately designed to provide three closely coupled CP modes, constituting a wide operating bandwidth. To facilitate the application in antenna array, a cavity-backed antenna design along with a 2×2 sub-array are further presented. To verify the design, a sub-array prototype is developed and tested at Ku-band for satellite applications, showing an impedance bandwidth of 25.1%, a wide 1-dB AR bandwidth of 15.6%, and a peak gain of 15.1dBi.