New dielectric material system of Nd(Mg1/2Ti1/2)O3–CaTiO3 at microwave frequency

The microwave dielectric properties of (1 − x)CaTiO3–xNd(Mg1/2Ti1/2)O3 (0.1 ⩽ x ⩽ 1.0) ceramics prepared by the conventional solid state method have been investigated. The system forms a solid solution throughout the entire compositional range. The dielectric constant decreases from 152 to 27 as x varies from 0.1 to 1.0. In the (1 − x)CaTiO3–xNd(Mg1/2Ti1/2)O3 system, the microwave dielectric properties can be effectively controlled by varying the x value. At 1400 °C, 0.1CaTiO3–0.9Nd(Mg1/2Ti1/2)O3 has a dielectric constant (εr) of 42, a Q × f value of 35 000 GHz and a temperature coefficient of resonant frequency (τf) of −10 ppm/°C. As the content of Nd(Mg1/2Ti1/2)O3 increases, the highest Q × f value of 43 000 GHz for x = 0.9 is achieved at the sintering temperature 1500 °C.