A new low-loss dielectric using CaTiO3-modified (Mg0.95Mn0.05)TiO3 ceramics for microwave applications

The microwave dielectric properties of the (1-x)(Mg0.95Mn0.05)TiO3-xCaTiO(3) ceramic system prepared by mixed oxide route have been investigated. The microstructures of the ceramics were characterized by SEM. Ilmenite-structured (Mg0.95Mn0.05)TiO3 and perovskite-structured CaTiO3 were coexisted and the two-phase system was confirmed by the XRD and EDX analysis. The microwave dielectric properties are strongly related to the density and matrix of the specimen. Combination of (Mg0.95Mn0.05)TiO3 and CaTiO3 forms a two-phase system and leads to a near-zero tau(f). With increasing x, the microwave Q x f decreased and epsilon(r) increased. A new microwave dielectric material, 0.93(Mg0.95Mn0.05)TiO3-0.07CaTiO(3) possesses excellent microwave dielectric properties with a dielectric constant (epsilon(r)) of similar to 22.67, a Q x f of similar to 90,700 GHz (where f = 9 GHz, is the resonant frequency) and a tau(f) value of similar to 0.8 ppm/degrees C at 1270 degrees C for 4 h. It is proposed as a suitable material candidate for applications requiring low microwave dielectric loss. (C) 2010 Elsevier B.V. All rights reserved.