Low temperature fired CaF2-based microwave dielectric ceramics with enhanced microwave properties

Abstract

Low-temperature-fired microwave ceramics are key to realizing the integration and miniaturization of microwave devices. In this study, a facile wet chemical method was applied to synthesize homogenous nano-sized CaF2 powders for simultaneously achieving low-temperature sintering and superior microwave dielectric properties. Pure CaF2 ceramics sintered at 950 °C for 6 h with good microwave dielectric properties (εr = 6.22, Q×f = 36,655 GHz, and τf = −102 ppm/°C) was achieved. The microwave dielectric properties of the CaF2 ceramics were further improved by introducing LiF as a sintering aid. The sintering temperature of CaF2-based ceramics was effectively lowered from 950 °C to 750 °C with 10 wt% LiF doping, and excellent microwave dielectric properties (εr = 6.37, Q×f = 65,455 GHz, and τf = −71 ppm/°C) were obtained.