Microwave dielectric ceramics in the BaO-TiO2-ZnO system doped with Nb2O5

The microwave dielectric properties of BaO-TiO(2)-ZnO (BTZ) system ceramics were studied as a function of the amount of Nb(2)O(5) dopant. With the addition of 0-0.025 mol% Nb(2)O(5), the substitution of Ti(4+) ions with Nb(5+) ions decreased the sintering temperature and increased the dielectric constant epsilon(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(2)O(5) was sintered at 1160 degrees C for 6 h, the epsilon(r), Qf(0), and the temperature coefficient of resonant frequency (tau(f)) were 36.7, 41,000 GHz, and -5.0 ppm/degrees C, respectively, at 5 GHz.