A novel millimeter-wave dual-band circularly polarized dielectric resonator antenna

In this article, a novel dual-band circularly polarized (CP) dielectric resonator antenna (DRA) for millimeter-wave (MMW) band is presented. The rectangular dielectric resonator with layered truncated corners is excited by a microstrip-coupled cross-slot. CP radiations in the lower band are realized by utilizing two quasi-TE111 modes operating at 21.7 GHz and 23.8 GHz, while CP radiations in the upper band are obtained by exciting a quasi-TE113 mode at 28.2 GHz. The dual-band DRA is fabricated and measured. Due to the higher order mode, the average gain of the DRA in the upper band is about 3 dB higher than that in the lower band. The measured impedance bandwidths (|S-11| < -10 dB) are 17.0% (20.5-24.3 GHz) and 15.2% (26.1-30.4 GHz), while the measured axial ratio (AR) bandwidths (AR < 3 dB) are 12.8% (21.2-24.1 GHz) and 5% (27.4-28.8 GHz). In addition, the peak gain values are 5 and 8 dBic.