BaO-TiO2-WO3 Microwave Ceramics and Crystalline BaWO4.

Microwave ceramic resonators composed of BaO-TiO2-WO3 were developed. The effect of WO3 addition on the system of BaO·xTiO2·(1+x)yWO3 (x=4 and 4.5, y=0 to 0.04) was studied. The ceramics of this system are composed of crystallines including Ba2Ti9O20, BaTi4O9, BaWO4, and TiO2. At y=0.02, the BaO·4TiO2·0.1WO3 ceramic was found to have excellent microwave properties such as e=35, Q=8400 at 6 GHz, and nearly 0 ppm/°C of τf.