Characterization and dielectric behavior of a new dielectric ceramics MgTiO3-Ca0.8Sr0.2TiO3 at microwave frequencies

The crystal structures, phase compositions and the microwave dielectric properties of the (1 − x)MgTiO3-xCa0.8Sr0.2TiO3 composites prepared by the conventional solid state route have been investigated. The formation of solid solution is confirmed by the XRD patterns. A rapid grain growth is observed at temperatures higher than 1300 °C, which would lead to a decrease in the density and Q × f of the ceramics. The temperature coefficient of resonant frequency (τf) increases with increasing Ca0.8Sr0.2TiO3 content and tunes through near zero at x = 0.06. Specimen using 0.94MgTiO3-0.06Ca0.8Sr0.2TiO3 possesses an excellent combination of microwave dielectric properties: ɛr ∼21.9, Q × f ∼128,000 GHz and τf ∼0.7 ppm/°C. It is proposed as a suitable candidate material for small-sized GPS patch antennas.