High-bandwidth microwave dielectric resonator antennas from BiVO₄/ZnO composites

This study reports the dielectric and structural characterisation of composites formed by the mixture of a BiVO₄ ceramic matrix with ZnO (25, 50, and 75 wt.%) obtained through a solid-state method procedure for applications in the microwave range. X-ray diffraction is used for structural characterisation. The dielectric properties and temperature coefficient of resonant frequency indicate a composition with ZnO close to zero. Dielectric constants varying with ZnO composition (7 to 67) and dielectric loss of ~ 10⁻² are measured, and the results confirm that the ZnO can improve the thermal stability of the composites. The composites are analysed as dielectric resonator antenna, where the experimental and theoretical characteristics of the resonator, like return loss, bandwidth, and input impedance, are in good agreement. Experimentally, for the BiVO₄ reference sample, bandwidths of 12.5% and 40.82% are found for the addition of 75 wt.% ZnO for a frequency operation of ~ 5.52 GHz.