A Wideband Circularly Polarized Dielectric Resonator Antenna

Abstract

In this letter, a wideband circularly polarized (CP) dielectric resonator antenna (CPDRA) with flat gain is proposed. Two CP modes can be combined together for broadband operation, which are the fundamental orthogonal hybrid $\mathrm{TE}^{\mathrm{y}} 111$, $\mathrm{TE}^{\mathrm{x}} 111$ modes and higher order $\mathrm{TE}^{\mathrm{y}} 113, \mathrm{TE}^{\mathrm{x}} 113$ modes of DR, respectively. Conformal microstrip on both sides of the DR is used as a feeding of two pairs of orthogonal modes to excite the DR. Furthermore, with a double-layer DR structure, a flat gain curve can be obtained. The -10 dB impedance bandwidth of the simulated antenna is 40.8% (3.18-4.81 GHz), an axial ratio (AR) bandwidth of 27% (3.16–4.17 GHz), and a flat gain reaches 7.05 dBi in the passband.