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

• High permittivity 0.2Ca0.8Sr0.2TiO3–0.8Li0.5Sm0.5TiO3 microwave ceramics were prepared by the conventional solid-state route.
• Adding proper amounts of BaCu(B2O5) and TiO2 lowers sintering temperature to 950 °C and improves dielectric properties.
• The microwave material is compatible with Ag electrode.

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.

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