Structure and Microwave Dielectric Characteristics of Ca[(Ga1/2 Nb1/2 )1−x Ti x ]O3 Ceramics

The microwave dielectric characteristics of Ca[(Ga1/2Nb1/2)1−xTix]O3 ceramics were investigated together with the structure evolution. The excellent microwave dielectric characteristics were achieved by forming solid solution between Ca(Ga1/2Nb1/2)O3 and CaTiO3 in the present ceramics. The solid solutions in space group Pbnm with antiphase and inphase tilting were determined for all compositions where minor secondary phase was detected for x = 0–0.47, whereas no B-site ordering was detected. Owing to the structural modification, the dielectric constant (er) increased with increasing x, and the temperature coefficient of resonant frequency (τf) could be tuned from negative to positive, while the decrease of Qf value was acceptable. The best combination of microwave dielectric properties was obtained at x = 0.47: er = 51.6, Qf = 34 100 GHz and τf = −0.3 ppm/°C.