Microwave dielectric properties of BaO-Ta2O5-TiO2 system

Microwave dielectric properties of the BaO-Ta2O5-TiO2 system were investigated by the solid-state reaction method. It was recognized that the Ba10Ta7.04(Ti1.2-xSnx)O-30 solid solutions have the higher Q(.)f value in comparison with the Ba-8(Ta4-xNbx)Ti3O24 solid solutions. The limit of the Ba10Ta7.04(Ti1.2-xSnx)O-30 solid solutions was approximately x = 0.75; the lattice parameter c of the solid solutions, which is related to the change in the B(1)O-6 octahedron, was significantly increased in the composition range from 0 to 0.75. The Q(.)f values of the Ba10Ta7.04(Ti1.2-xSnx)O-30 solid solutions are remarkably improved by the Sn substitution for Ti; the highest Q(.)f value of 59,100 GHz is obtained at x = 0.75. Moreover, the epsilon(r) and tau(f) values of the Ba10Ta7.04(Ti1.2-xSnx)O-30 solid solutions at x = 0.75 were 25.6 and 30.3 ppm/degrees C, respectively. (c) 2005 Elsevier Ltd. All rights reserved.