Low-firable high-K dielectric in the Zr_x(Zn_1/3Nb _2/3)_1-xTiO₄ ceramic system

Composite ceramics in the solid solution of Zr_x(Zn _1/3Nb_2/3)_1-xTiO₄ (x = 0.1-0.4) have been prepared by the mixed oxide route. Formation of solid solution was confirmed by the X-ray diffraction patterns. The microwave dielectric properties, such as dielectric constant (ε_r), Q × f value and temperature coefficient of resonant frequency (τ_f) have been investigated as a function of composition and sintering temperature. With x increasing from 0.1 to 0.4, the dielectric constant decreases from 70.9 to 43.2, and the τ_f decreases from 105 to 55 ppm/°C. The Q × f value, however, increases with increasing x value to a maximum 26,600 GHz (at 6 GHz) at x = 0.3, and then decreases thereafter. For low-loss microwave applications, a new microwave dielectric material Zr_0.3(Zn _1/3Nb_2/3)_0.7TiO₄, possessing a fine combination of microwave dielectric properties with a high ε_r of 51, a high Q × f of 26,600 GHz (at 6 GHz) and a τ_f of 70 ppm/°C, is suggested.