Microwave dielectric properties of SnO2-doped CaSiO3 ceramics

SnO 2 -doped CaSiO 3 ceramics were successfully synthesized by a solid-state method. Effects of different SnO 2 additions on the sintering behavior, microstructure and dielectric properties of Ca(Sn 1− x Si x )O 3 ( x =0.5–1.0) ceramics have been investigated. SnO 2 improved the densification process and expanded the sintering temperature range effectively. Moreover, Sn 4+ substituting for Si 4+ sites leads to the emergence of Ca 3 SnSi 2 O 9 phase, which has a positive effect on the dielectric properties of CaO–SiO 2 –SnO 2 materials, especially the Qf value. The Ca(Sn 0.1 Si 0.9 )O 3 ceramics sintered at 1375   °C possessed good microwave dielectric properties: ε r =7.92, Qf =58,000   GHz and τ f =−42   ppm/°C. The Ca(Sn 0.4 Si 0.6 )O 3 ceramics sintered at 1450   °C also exhibited good microwave dielectric properties of ε r =9.27, Qf =63,000   GHz, and τ f =−52   ppm/°C. Thus, they are promising candidate materials for millimeter-wave devices.