Structure and Microwave Dielectric Characteristics of Ca[(Ga 1/2 Nb 1/2 ) 1− x Ti x ]O 3 Ceramics

The microwave dielectric characteristics of Ca[(Ga 1/2 Nb 1/2 ) 1− x Ti x ]O 3 ceramics were investigated together with the structure evolution. The excellent microwave dielectric characteristics were achieved by forming solid solution between Ca(Ga 1/2 Nb 1/2 )O 3 and CaTiO 3 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 (ε r ) increased with increasing x , and the temperature coefficient of resonant frequency (τ f ) 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: ε r   = 51.6, Qf  = 34 100 GHz and τ f   = −0.3 ppm/°C.