Mixture behavior and microwave dielectric properties in the low-fired TiO2-CuO system

The mixture behavior and microwave dielectric properties of TiO2 doped with CuO sintered at around 900 degrees C for 2 h were investigated using X-ray powder diffraction and a network analyzer. Low-fired TiO2 with 2% CuO had a quality factor of 14000, relative dielectric constant (epsilon(r)) of 98, and a temperature coefficient of resonant frequency (tau(f)) Of 374 ppm/degrees C. The microwave dielectric properties of low-fired, CuO doped TiO2 could be interpreted by observing the dielectric properties of CuO: high loss tangent (tan delta), low dielectric constant, and a negative temperature coefficient of resonant frequency. The microwave dielectric properties of low-fired, CuO doped TiO2 showed a dependence on the mixture formation of TiO2 and CuO. More importantly, the epsilon(r) of low-fired TiO2 with CuO could be predicted by the logarithmic mixing model. Therefore, the variation of the microwave dielectric properties was attributed to the mixture behavior of TiO2 and CuO.