Crystal structure and microwave dielectric properties of Zn0.9Ti0.8−xSnxNb2.2O8 ceramics

The crystal structure and microwave dielectric properties of Zn0.9Ti0.8−xSnxNb2.2O8 (x = 0.00, 0.05, 0.10, 0.15) ceramics sintered at temperatures ranging from 1100 °C to 1140 °C for 6 h were investigated. A single phase with ixiolite structure was obtained. With the increase of Sn content, the dielectric constant decreased attributed to the decrease of dielectric polarizability. The Qf value decreased with the decrease of packing fraction and grain size. The temperature coefficient of resonant frequency (τf) increased due to the increase of the bond valence of Zn0.9Ti0.8−xSnxNb2.2O8 ceramics. The excellent microwave dielectric properties of ɛ = 35.05, Qf = 49,100 GHz, τf = −27.6 × 10−6/°C were obtained for Zn0.9Ti0.8−xSnxNb2.2O8 (x = 0.05) specimens sintered at 1120 °C for 6 h.