Wideband circularly polarized dielectric resonator antenna with high gain for microwave wireless power transfer

Wireless power transmission (WPT) is poised to revolutionize the future of wireless applications and sensing networks. High-gain antennas are essential for extending WPT coverage, but the unpredictable orientation of wireless devices remains a major challenge. To address this, this paper proposes a dielectric resonator antenna (DRA) with a new cone version (cupped-cone shape) to achieve high gain and a wideband circular polarization, ensuring consistent energy transfer regardless of device orientation. The proposed design enhances bandwidth by supporting multiple resonant modes. Combining two geometric shapes provides greater flexibility for fine-tuning and optimizing the DRA. The proposed DRA is excited using an innovative feeding mechanism with two elliptical slots and a modified microstrip feeding to produce wideband circular polarization, achieving large impedance and axial ratio bandwidths. The design is fabricated from polylactic acid using 3D printing technology, making it lightweight and cost-effective. Measurements show the antenna operates in the WPT band, covering the industrial, scientific, and medical (ISM) frequency of 5.8 GHz with a 64% impedance bandwidth, 3-dB axial ratio bandwidth of approximately 31%, and a high gain of about 11.1 dBic by effectively utilizing a higher-order mode while maintaining the bandwidth.