Effect of High-Q Ba4Ti13O30 Materials on The Dielectric Properties of (Bax,Sr1−x)Tio3 Films For Microwave Communication

Abstract

Nano-sized BaTiO₃, SrTiO₃ and TiO₂ powders have been used to synthesize (Ba _x ,Sr_1−x )TiO₃ materials via mixed oxide process. Then (Ba _x ,Sr_1−x )TiO₃ (BST) (x = 0.5 and 0.6) with addition of high-Q (quality factor) Ba₄Ti₁₃O₃₀ (BT) materials were screen printed on Al₂O₃ substrates. The prepared thick films of BST/BT with three layered and five layered composite materials were sintered at 1275°C (4 h). The microwave dielectric properties of the bulk ceramics and the thick films were measured by resonant cavity method at higher microwave frequencies (9.5 GHz). The three layered thick films have dielectric constant of 13.4 for x = 0.5 and 15.5 for x = 0.6. The five layered thick films possess dielectric constant of 12.7 for x = 0. 5 and 15.8 for x = 0.6. The frequency × quality factor (f × Q) increases markedly with a larger magnitude of 1600 for the three layered thick films than the five layered ones. The results imply that the BST/BT composite thick films have potential application in tunable microwave devices.