Low-temperature sintering and microwave dielectric properties of CaSnxSiO(3+2x)-based positive τf compensator

The sinterability, phase compositions, and microwave dielectric properties of LiF-doped nonstoichiometric CaSnxSiO(3+2x) ceramics prepared by the solid-state reaction were investigated. LiF addition effectively reduced the sintering temperature of CaSnxSiO(3+2x) ceramics and inhibited the volatilization of Sn. A pure monoclinic CaSnSiO5 phase was achieved in the 1.0 wt% LiF-doped CaSn0.94SiO4.88 ceramics sintered at 1175 °C, which exhibited good microwave dielectric properties of εr = 11.6, Q × f = 34000 GHz, and τf = +73.2 ppm/°C. The positive τf value was an atypical and important phenomenon for low-permittivity microwave dielectric ceramics, which could be a promising τf compensator.