Microwave dielectric properties of (1−x)SiO2−xTiO2 ceramics

Abstract

The microstructures, phase compositions and microwave dielectric properties of (1−x)SiO2−xTiO2 (0≤x≤0.20) composite ceramics prepared by a conventional oxide mixing method were investigated. XRD patterns conformed that SiO2 and TiO2 phases co-existed as a two-phase system and some Ti4+ ions entered the SiO2 lattice. Addition of TiO2 eliminated the formation of tridymite phase. As TiO2 content x increased, the εr and τf values increased gradually, while the Q×f values declined inversely. Under the same amount of TiO2 content, the εr and Q×f values increased initially and then decreased slightly with increasing the sintering temperature, whereas the τf values increased slowly. The 0.84SiO2–0.16TiO2 ceramics sintered at 1275°C for 3h possess good dielectric properties of εr=5.91, Q×f=39,680GHz (measured at 12.52GHz), and τf=−4.53ppm/°C.