Microwave dielectric ceramics in the BaO-TiO_2-ZnO system doped with Nb_2O_5

摘要

Abstract The microwave dielectric properties of BaO-TiO_2-ZnO (BTZ) system ceramics were studied as a function of the amount of Nb_2O_5 dopant. With the addition of 0-0.025 mol% Nb_2O_5, the substitution of Ti~(4+) ions with Nb~(5+) ions decreased the sintering temperature and increased the dielectric constant ε_r and quality factor Q of the system due to the similar atomic radius of Nb~(5+) and Ti~(4+) ions. When the amount of Nb~(5+) increased further (>0.025 mol%), Q was decreased by increasing the titanium vacancies. When the system doped with 0.025 mol% Nb_2O_5 was sintered at 1160 ℃ for 6 h, the ε_r, Qf_0, and the temperature coefficient of resonant frequency (τ_r) were 36.7, 41,000 GHz, and -5.0 ppm/℃, respectively, at 5 GHz.