Compact Wideband Circularly Polarized Dielectric Resonator Antenna with Dielectric Vias

Using dielectric vias, we propose a compact and wideband circularly polarized (CP) dielectric resonator antenna (DRA). The dielectric vias are realized by filling barium strontium titanate nanoparticles with a dielectric constant of 20 into a perforated printed circuit board (PCB) substrate. Owing to the high effective dielectric constant of the dielectric via-loaded PCB substrate, the electrical size of the DRA is reduced. The arrangement of dielectric and air vias inside the DRA structure allows for redistributing the resonant frequencies of different radiating modes. This design incorporates a third higher-order mode into the passband, resulting in wide impedance and axial ratio (AR) bandwidths. A cross slot is used to excite the CP fields. The standard PCB process is utilized to manufacture the antenna structure. The fabricated prototype has measured impedance and AR bandwidths of 46.9% and 26.7%, respectively. The measured overlapping bandwidth is 25.4%. Our prototype has a compact footprint of 0.61 × 0.61 λ²₀ where λ₀ is the wavelength in free space at the center frequency. The proposed dielectric vias technique has potential abilities in size reduction and bandwidth enhancement.