Improved high Q value of CaTiO3–Ca(Mg1/3Nb2/3)O3 solid solution with near zero temperature coefficient of resonant frequency

The crystal structures and the microwave dielectric properties of (1−x)CaTiO3–xCa(Mg1/3Nb2/3)O3 perovskite ceramic system have been investigated. (1−x)CaTiO3–xCa(Mg1/3Nb2/3)O3 solid solution exhibited orthorhombic crystal structures for all compositions. With x = 0.66, a new microwave dielectric ceramic material 0.34CaTiO3–0.66Ca(Mg1/3Nb2/3)O3 applicable to microwave devices is suggested and possesses the dielectric properties of a dielectric constant εr ∼ 48, a Q×f values ∼ 32,500 (at 6.7 GHz) and a τf value ∼−2 ppm/°C at 1450°C for 3 h. Further improvement of the Q×f value can be achieved by extending the sintering time to 6 h. It reveals a higher Q×f value of 34,000 (at 6.7 GHz) without degrading other microwave dielectric properties of 0.34CaTiO3–0.66Ca(Mg1/3Nb2/3)O3 ceramics.