MICROWAVE CHARACTERISTICS OF TIO2-BI2O3 DIELECTRIC RESONATOR

The microwave characteristics of the binary-system TiO2-Bi2O3 ceramics , which is widely known to exhibit a comparatively high dielectric con stant in the lower-frequency band, are investigated from a new standpo int. It is shown in this article that the composition of 0.919TiO2-0.0 81Bi2O3 has a high dielectric constant (epsilon(r)=80), high Q (1800 a t 5 GHz) and low temperature coefficient of resonant frequency (tau(f) = +21 ppm/degrees-C). From the X-ray diffraction and X-ray microanaly sis, it is indicated that the crystal structure of this material is co mposed of two phases, TiO2 and Bi2Ti4O11, which possess a high epsilon (r) with a negative temperature coefficient and a high epsilon(r) with a positive temperature coefficient, respectively. The measurements of linear thermal expansion and temperature coefficient of capacitance a re also carried out in order to study the behavior of temperature comp ensation in this system.