Shih-Sheng Liu

Dielectric Properties of a New Ceramic System (Mg0.95Zn0.05)2TiO4–CaTiO3 at Microwave Frequencies

The microwave dielectric properties and microstructure of a two-phase (Mg0.95Zn0.05)2TiO4–CaTiO3 ceramic system prepared using the conventional solid-state route were investigated. The structure and microstructure were analyzed by X-ray diffraction and scanning electron microscopy, respectively. Ilmenite-structured (Mg0.95Zn0.05)TiO3 was detected as a second phase. The coexistence of the second phase, however, did not degrade the dielectric properties of the specimen because the phases were compatible. At 1270 °C, 0.92(Mg0.95Zn0.05)2TiO4–0.08CaTiO3 ceramic showed a good combination of microwave dielectric properties: a dielectric constant (er) of ~18.03, a quality factor (Q ×f) value of ~153,000 GHz (at 10 GHz), and a temperature coefficient of resonant frequency (τf) of ~ -16.82 ppm/°C. The τf value is strongly correlated to the composition and can be controlled by the compositional ratio. At x = 0.1, an er of ~19.15, a Q ×f value of ~94,400 GHz (at 10 GHz), and a τf of ~1.5 ppm/°C were obtained for 0.9(Mg0.95Zn0.05)2TiO4–0.1CaTiO3 ceramic sintered at 1270 °C for 4 h.