Dielectric properties of Barium Strontium Calcium Titanate ceramics with compositional inhomogeneity

Compositionally inhomogeneous Barium Strontium Calcium Titanate (BSCT) ceramics with weak dielectric temperature sensitivity and high tunability were synthesized by the phase-mixed method. Effects of Ca adding and adding ways on microstructures, dielectric properties and tunabilities of these BSCT ceramics were investigated. Results show that Ca adding can decrease the dielectric constant from ~2800 to ~1500 enhance the dielectric temperature stability and still retain the tunability as high as 20% under the DC electric field of 10kV/cm. The temperature-dependent dielectric constants of BSCT ceramics also depend on Ca adding ways. BSCT-MixCa ceramics sintered at 1260°C with a moderate dielectric constant of 1500 exhibit little temperature dependence of dielectric constants and high tunability of 18.8%. Such properties indicate that compositionally inhomogeneous BSCT ceramics are potential materials for tunable microwave applications.