Microwave Dielectric Properties and Mixture Behavior of CaWO₄–Mg₂SiO₄ Ceramics

In order to use at a high microwave frequency range, the microwave dielectric properties and the microstructures of the (1- x )CaWO 4 – x Mg 2 SiO 4 ceramics with dielectric constants below 10 were investigated. The (1- x )CaWO 4 – x Mg 2 SiO 4 ceramics have tetragonal structure, and quantitative and morphology analyses were performed using a scanning electron microscope (SEM), wave dispersive X-ray spectrometer (WDX) and backscattered electron image micrographs. The highest quality microwave dielectric properties of the (1- x )CaWO 4 – x Mg 2 SiO 4 ceramics as a function of the composition x agree well with the highest density and the highest extent of shrinkage at the most optimum sintering temperature. At the composition of x =0.1, the (1- x )CaWO 4 – x Mg 2 SiO 4 ceramics have excellent microwave dielectric properties: ε r =10.0, Q · f =129858 GHz and τ f =-49.6 ppm/°C.