High thermal stability of the microwave dielectric properties of ZnNb₂O₆ with CaTiO₃ addition

This paper presents a study of the dielectric properties of ZnNb₂O₆ (ZNO) with added CaTiO₃ (CTO) in the microwave (MW) region. An X-ray diffraction analysis is performed, and a reaction between ZNO and CTO is demonstrated that results in the formation of other crystalline phases. The dielectric properties in the MW region show no significant change in permittivity (ε'_r), whereas the addition of CTO results in an increase in the dielectric loss (tan δ). The thermal stability is also measured, and the temperature coefficient of resonant frequency (τ_f) is varied from −88.95 to −8.16 ppm °C⁻¹. Numerical simulations are carried out to evaluate these materials for use as a dielectric resonator antenna, and the results show a reflection coefficient (|S₁₁|) of below −10 dB, a radiation efficiency above 96 %, a bandwidth ranging from 100 to 170 MHz, and a gain of above 4.50 dBi. The values obtained here show that these materials could be employed in electronic devices acting in the C- and S-bands.