Microwave dielectric properties of Zn(Nb1−xTax)2O6 ceramics

Microwave dielectric ceramics Zn(Nb1-xTax)2O6 were prepared by the conventional mixed oxide route. The crystal structure and microwave dielectric properties were investigated systematically using XRD and a network analyser. Two kinds of solid solutions based on the ZnNb2O6 and ZnTa2O6 structure, respectively, were observed in this binary system. The sintering temperature of ceramics increased from 1150 to 1350 C as the x value ranged from 0 to 1.0. The dielectric properties exhibited a significant dependence on the sintering condition, composition and crystal structure of the ceramics. The dielectric constant increased with increasing Ta content, and ranged from 23.05 at x = 0 to 35.8 at x = 1. The quality factors (Qxf) of this system decreased with increasing Ta content, the highest Qxf values of sintered ceramics changed linearly, and ranged from 82200 to 56417 GHz as the x values increased from 0 to 1.0. The temperature coefficient of resonant frequency changed from -71.16 ppm/C at x = 0 to +8.94 ppm/C at x = 1, and a zero value was obtained at x = 0.65. 9 refs.