ZnZr1−xHfxNb2O8-yTiO2-ZnZr1−xHfxNb2O8 (0.000 [formula omitted] x [formula omitted] 0.030, 0.01 [formula omitted] y [formula omitted] 0.06): An high-Q and temperature-stable microwave dielectric ceramic through laminated co-firing technique

Abstract

In order to better fulfill the requirements high-performance dielectric devices for low insertion loss, compact size, and excellent temperature stability, we propose a strategy to maximize the comprehensive regulation of microwave dielectric properties. Since TiO2 has a relatively large and positive τf value, direct addition of TiO2 has often been utilized to modify the negative τf value in previous studies. In this paper, TiO2 and the laminated co-firing technique are applied to monoclinic wolframite structural ceramics. Tri-layer architectural ZnZr1−xHfxNb2O8-yTiO2-ZnZr1−xHfxNb2O8 (0.000 ≤ x ≤ 0.030, 0.01 ≤ y ≤ 0.06) ceramics were synthesized by the laminated co-firing technique. Firstly, Hf4+ ions substituted for Zr4+ ions to significantly enhance the Q×f value of ZnZrNb2O8 system. The modulation effect of Hf4+ on the crystal structure and the influence on the dielectric constant (εr), Q×f, and τf values were reasonably demonstrated by combining several characterization approaches with complex chemical bond theory. Compared with pure ZnZrNb2O8, the ZnZr0.990Hf0.010Nb2O8 ceramic achieved a nearly 65% increase in the Q×f value without excessive deterioration of other dielectric parameters. The laminated co-firing technique was then used to further modulate its εr and τf values. Notably, the ZnZr0.990Hf0.010Nb2O8-0.05TiO2-ZnZr0.990Hf0.010Nb2O8 tri-layer architectural ceramic achieved prominent comprehensive microwave dielectric characteristics: εr = 34.34, Q×f = 53,860 GHz, and τf = + 2.29 ppm/°C, making the tri-layer architecture ceramics attractive for usage in modern microwave communications.