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.