Low-fired microwave dielectrics in ZnO-TiO2 ceramics doped with CuO and B2O3

The microwave dielectric properties and the microstructure of low-firing zinc titanate ceramics have been investigated. The microstructure of these ceramics have been studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and it was found that CuO addition has the important effect of stabilizing the Zn₂TiO₄ phase. When the sintering temperatures are in the range of 870–950 °C, dielectric constant values ( _r ) saturate at 21–25, the Q×f value is 20 000 GHz (at 10 GHz). The temperature coefficient of resonant frequency ( _f ) was 10 ppm °C^–1. Therefore, the 0.5 wt %-CuO and 1.0 wt %-B₂O₃ doped ZnO-TiO₂ ceramics can be used in multi-layer microwave devices requiring low sintering temperature.