Microwave dielectric properties and microstructures of Ca(Nb1−xTax)2O6 ceramics

This study elucidates the microwave dielectric properties and microstructures of Ca(Nb1−xTax)2O6 ceramics with a view to their potential for microwave devices. The Ca(Nb1−xTax)2O6 ceramics were prepared by the conventional solid-state method with various sintering temperatures. The X-ray diffraction patterns of the Ca(Nb0.93Ta0.07)2O6 ceramics revealed no significant variation of phase with sintering temperatures. A dielectric constant (ɛr) of 17.7, a quality factor (Q × f) of 117,000 GHz, and a temperature coefficient of resonant frequency (τf) of −51 ppm/°C were obtained for Ca(Nb0.93Ta0.07)2O6 ceramics that were sintered at 1,400 °C for 4 h.