Dielectric properties of a low-loss (1-x)(Mg0.95Zn0.05)2TiO4-x(Ca0.8Sr0.2)TiO3 ceramic system at microwave frequencies

Abstract

The microwave dielectric properties and microstructures of the (1-x)(Mg0.95Zn0.05)2TiO4-x(Ca0.8Sr0.2)TiO3 ceramics prepared using the conventional solid-state route were investigated. The structure and microstructure were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. Ilmenite-structured (Mg0.95Zn0.05)TiO3 was detected as a secondary phase. The coexistence of the second phase, however, did not degrade the dielectric properties of the specimen because the phases were compatible. At x = 0.07, a dielectric constant (er) of ~17.86, a quality factor (Q × f) value of 133,600 Hz (at 10 GHz), and a temperature coefficient of resonant frequency (τf) of ~ −3 ppm/°C were obtained for 0.93(Mg0.95Zn0.05)2TiO4–0.07(Ca0.8Sr0.2)TiO3 ceramic sintered at 1240 °C for 4 h. The dielectric is proposed as a candidate material for low –loss microwave applications.