Low-fire BiTaO4 dielectric ceramics for microwave applications

The dielectric properties at microwave frequencies and the microstructures of BiTaO4 ceramics with 0.5 wt.% doping of CuO have been investigated. The BiTaO4 ceramics can be sintered to approach 95% theoretical density at 960 degrees C. Sintered ceramic samples were characterized by X-ray and scannin g electron microscopy (SEM). The dielectric constant values (epsilon(r)) sa turate at 44-45. The Q X f values of 8000-12 000 (at 6 GHz) can be obtained when the sintering temperatures are in the range of 920-960 degrees C. The temperature coefficient of resonant frequency tau(f) was -40 ppm/degrees C . The BiTaO4 ceramics have applications for multilayer microwave devices re quiring low sintering temperatures. (C) 2000 Elsevier Science B.V. All righ ts reserved.