Low temperature sintering and microwave dielectric properties of 0.2Ca0.8Sr0.2TiO3–0.8Li0.5Sm0.5TiO3 ceramics with BaCu (B2O5) additive and TiO2 dopant

Low firing temperature 0.2Ca0.8Sr0.2TiO3–0.8Li0.5Sm0.5TiO3 (CST–LST) ceramics by BaCu (B2O5) addition and TiO2 dopant were prepared via the conventional solid-state ceramic route, and the sintering, phase evolution, microstructure, and dielectric properties were investigated. Addition of BaCu (B2O5) lowered the firing temperature about 300 °C. The CST–LST ceramics with 5 wt% BaCu(B2O5) sintered at 950 °C exhibited single phase perovskite structure, together with the optimum microwave dielectric properties of ϵr = 66.7, Q × f = 3222 GHz, τf = −21.3 ppm/°C. Adding TiO2 improved the microwave properties. Typically, the CST–LST + 5 wt% BaCu(B2O5) + 1.5 wt% TiO2 sintered at 950 °C showed ϵr = 71.6, Q × f = 3441 GHz, τf = −10.8 ppm/°C. The high permittivity and low temperatures of the ceramics were ideal for the development of low cost ultra-small dielectric loaded antenna. Compatibility with Ag electrode indicated that this material was suitable for low temperature co-fired ceramics.