Microwave dielectric materials based on the MgO–SiO2–TiO2 system

Ceramics in the system MgO–SiO2–TiO2 were prepared by standard mixed oxide route. By adding ZnO–B2O3 to the starting mixtures, the firing temperature of the ceramics could be reduced to 1160 °C. Small additions of MnCO3 and CaTiO3 improve microwave dielectric properties leading to an increase in insulation resistance and a decrease in temperature coefficient of capacitance. By adding Co2O3 grain growth can be inhibited and the dielectric Qf value greatly increased. The resultant ceramic material exhibited low dielectric constant and low dielectric loss: relative permittivity (εr): 20±2; temperature coefficient of capacitance (τc): 0±30 ppm/°C; Qf: 100,000 (at 10 GHz); insulation resistance: 1013 Ω cm: