Sn-doped BaO-TiO-ZnO (BTZ) microwave ceramic materials were investigated as a unction of SnO2 eontent. Addition of a small amounl of SnO2 (0.01-0.06 wt%) owered the sin(cring temperature of the system to 1160℃ and also greatly reduced he dielectric loss (tail δ), which is closely related to the insulation resistivity The n-doped BTZ materials were found to have excellent dielectric properties at 1 GHz ith dielectric constant e=36. loss tangent tan δ≤1×l0-4, lemperature coefficienl of dielectric constant, α, =0±30ppm/℃, and volunme resistivty pg≥1013Ωcm.