Microwave dielectric properties of SnO2-doped CaSiO3 ceramics

SnO2-doped CaSiO3 ceramics were successfully synthesized by a solid-state method. Effects of different SnO2 additions on the sintering behavior, microstructure and dielectric properties of Ca(Sn1-xSix)O-3 (x=0.5-1.0) ceramics have been investigated. SnO2 improved the densification process and expanded the sintering temperature range effectively. Moreover, Sn4+ substituting for Si4+ sites leads to the emergence of Ca3SnSi2O9 phase, which has a positive effect on the dielectric properties of CaO-SnO2-SnO2 materials, especially the Qf value. The Ca(Sn0.1Si0.9)O-3 ceramics sintered at 1375 degrees C possessed good microwave dielectric properties: epsilon(r)=7.92, Qf=58,000 GHz and tau(f)=-42 ppm/degrees C. The Ca(Sn0.4Si0.6)O-3 ceramics sintered at 1450 degrees C also exhibited good microwave dielectric properties of epsilon(r)=9.27, Qf= 63,000 GHz, and tau(f)=-52 ppm/degrees C. Thus, they are promising candidate materials for millimeter-wave devices. (C) 2012 Elsevier Ltd and Techna Group S.r.l. All rights reserved.