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

Abstract

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 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 $2 \\times 2$ subarray are further presented. To verify the design, a subarray 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 15.1 dBi.