A novel low-loss microwave dielectric using (Ca0.8Sr0.2)TiO3-modified (Mg0.95Co0.05)2TiO4 ceramics

The microwave dielectric properties of conventional solid-state route prepared (1 − x)(Mg0.95Co0.05)2TiO4–x(Ca0.8Sr0.2)TiO3 ceramic system have been investigated. A two-phase system was confirmed by the X-ray diffraction patterns. (Mg0.95Co0.05)TiO3 was also detected as a second phase in the system. The microwave dielectric properties are strongly related to the density and the morphology of the specimens. The presence of the second phase, however, would cause no significant variation in the dielectric properties of the specimen because it possesses similar properties compared to that of the main phase (Mg0.95Co0.05)2TiO4. Specimen using 0.92(Mg0.95Co0.05)2TiO4–0.08(Ca0.8Sr0.2)TiO3 leads to a good combination of microwave dielectric properties with an ɛr of 19.22, a Q × f of 123,200 GHz (at 9.2 GHz) and a τf value of 2.8 ppm/°C. It is proposed as a candidate dielectric for applications in GPS patch antennas and 3G passive components.