A new dielectric material system using (1 − x)(Mg0.95Co0.05)2TiO4–xCa0.8Sm0.4/3TiO3 at microwave frequencies

The microwave dielectric properties of the (1 − x)(Mg0.95Co0.05)2TiO4–xCa0.8Sm0.4/3TiO3 ceramic system prepared by mixed oxide route have been investigated. The crystal structures and the microstructures of the ceramics were characterized by means of X-ray and SEM, respectively. The microwave dielectric properties are strongly related to the density and the matrix of the specimen. Combining (Mg0.95Co0.05)2TiO4 (spinel structure) and Ca0.8Sm0.4/3TiO3 (perovskite structure) forms a two-phase system and leads to a near-zero τf. With increasing x, the Q × f of the specimen decreased, whereas its ɛr increased due to a compositional variation. A new microwave dielectric 0.8(Mg0.95Co0.05)2TiO4–0.2Ca0.8Sm0.4/3TiO3, possessing excellent microwave dielectric properties with a dielectric constant (ɛr) of 20.84, a Q × f of 112,600 GHz (where f = 9.1 GHz, is the resonant frequency) and a τf value ∼0.8 ppm K−1 at 1573 K/4 h, is proposed as a candidate material for GPS patch antennas and 3G passive components.