Triple-band dual-sense circularly polarized hybrid dielectric resonator antenna

In this paper, a triple-band dual-sense circularly polarized (CP) hybrid dielectric resonator antenna is proposed. A modified hexagonal dielectric resonator (DR) is top-loaded with a square microstrip ring (SMR). A vertical-tapered-strip connected to a 50-Ω microstrip line is used to excite the proposed antenna. It is found that the lower and central CP bands correspond to left-handed circular polarization and are produced by the TM₁₁ and TE₁₁₁ modes of the SMR and modified hexagonal DR, respectively. The upper CP band is formed by the combination of the quasi-TM₂₁ mode of the SMR and quasi-TE₁₁₁ mode of the DR that exhibits right-handed circular polarization. The measurement results of the fabricated prototype show triple-band response for |S₁₁ | < −10 dB with impedance bandwidths (IBWs) of 17.4% (1.75–2.03 GHz), 28.13% (2.23–2.96 GHz), and 2.97% (3.65–3.76 GHz) in the lower, central, and upper bands, respectively. The measured 3 dB axial ratio bandwidths lying within −10 dB IBWs are 3.69% (1.86–1.93 GHz), 5.46% (2.67–2.82 GHz), and 2.15% (3.68–3.76 GHz) along with the peak gains of 5 dBic, 5.28 dBic, and 2.36 dBic in the lower, central, and upper bands, respectively.