Microwave dielectric ceramics in (Ca1− xBax)(Zn1 / 3Nb2 / 3)O3 system

(Ca1−xBax)(Zn1 / 3Nb2 / 3)O3 (x = 0–1.0) microwave dielectric ceramics were prepared and investigated. The Ba(Zn1 / 3Nb2 / 3)O3-based solid solution was observed for x = 0.9, and the compositions with x = 0.1–0.7 resulted in the mixture of two phases. Dielectric constant εr and temperature coefficient of resonant frequency τf of the present ceramics varied anomalously and reached their maximum at x = 0.7–0.9, and these phenomena were originated from the partial substitution of small Ca2+ ions for larger Ba2+ at A-site. On the other hand, a good combination of microwave dielectric properties (εr = 36, Qf = 16,170 GHz, τf = − 12 ppm/°C) were obtained at x = 0.1, while the decreased Qf value was observed in other compositions.