Improved High-Q Dielectric Resonator Sintered at Low Firing Temperature

Abstract

The microwave properties of Ba(Co 1/3 Nb 2/3 )O 3 -Ba(Ni 1/3 Nb 2/3 )O 3 ceramics were investigated. Ba(Co 1/3 Nb 2/3 )O 3 has a low sintering temperature. However, the Q value is too low for application requirements at microwave frequencies. A new composition, Ba(Ni 1/3 Nb 2/3 )O 3 , which shows a positive temperature coefficient of resonant frequency was used as a compensator to improve the dielectric properties of the complex perovskite-type ceramic. Both sintering and crystallization of Ba(Co 1/3 Nb 2/3 )O 3 -Ba(Ni 1/3 Nb 2/3 )O 3 were accelerated compared to those of Ba(Co 1/3 Nb 2/3 )O 3 alone. The Q value at microwave frequencies was also improved. The dielectric ceramics with Ba(Co, Ni) 1/3 Nb 2/3 O 3 system were found to be fired at a low temperature below 1400° C and to have a low temperature coefficient of resonant frequency τ f and high Q value. Dielectric properties of the ceramic resonator made of Ba(Co 0.6 Ni 0.4 ) 1/3 Nb 2/3 O 3 are a dielectric constant of 31, Q value of 10000 at 9 GHz, and temperature coefficient of resonant frequency τ f of -4 ppm/° C.