Dielectric properties of CaTiO3-Ca(Mg1/3Nb2/3)O3 ceramic system at microwave frequency

The crystal structures and the microwave dielectric properties of the (1 - x)CaTiO3-xCa(Mg1/3Nb2/3)O-3 perovskite ceramic system have been investigated. The (1 - x)CaTiO3-xCa(Mg1/3Nb2/3)O-3 solid solution exhibited orthorhombic crystal structures for all compositions. As the x value increases from 0.2 to 0.8, the dielectric constant epsilon (r) decreases from 109 to 36 and the unloaded quality value Q x f increases from 8600 to 39000 (at 6.7 GHz). The temperature coefficient of the resonant frequency (tau (f)) varies from 298 to -30 ppm/degreesC as the x value increases from 0.2 to 0.8. A new microwave dielectric material, 0.4CaTiO(3)-0.6Ca(Mg1/3Nb2/3)O-3, applicable in microwave devices is suggested and possesses the dielectric properties of a dielectric constant epsilon (r) similar to 54, a Q x f value similar to 32000 (at 6.7 GHz) and a tau (f) value similar to 18 ppm/degreesC. Further improvement of the tau (f) value is expected by adjusting the x value of(1 - x)CaTiO3-xCa(Mg1/3Nb2/3)O-3 ceramics.