Papers by Author: Chen Ai

Abstract: Pure barium strontium titanate (Ba0.65Sr0.35TiO3) and MnO2-modified barium strontium titanate (Ba0.65Sr0.35TiO3-MnO2) thick films were fabricated by electrophoretic deposition technique. The structures and morphologies of the films were analyzed. The dielectric measurements were conducted on metal-insulator-metal capacitors using platinum as the bottom electrodes and gold as the top electrodes. The dielectric constants and dissipation factors of Ba0.65Sr0.35TiO3 and Ba0.65Sr0.35TiO3-15wt% MnO2 thick films were measured at a frequency of 1 MHz. The tunabilities of 12.5% and 9.3% were obtained for Ba0.65Sr0.35TiO3 and Ba0.65Sr0.35TiO3-MnO2 thick films under an applied electric field of 15 kV/cm, respectively. The dielectric properties of the present thick films were suitable for tunable microwave device applications.

Abstract: In this work, tape-casting technique was employed to prepare Ba0.7Sr0.3TiO3 films for lens antenna system. Effects of slurry properties on the tape casting procedure were investigated and the thickness, tensile strength and the surface roughness of the tapes were studied. The structure, morphology and the dielectric properties of the films were analyzed.

Abstract: Ba1-xSrxTiO3 ceramic (BST) was one of the promising materials applied in phased array antennas due to its excellent dielectric properties. Ba1-xSrxTiO3 ceramic was prepared by traditional solid state reactions. Effects of different amount of ZrO2 as additive upon the dielectric properties of BST were investigated. The analyzed results showed that, as the amount of ZrO2 increasing, the dielectric constant and temperature dependence of dielectric constant of this ceramic both decreased, while its dielectric tunability kept high value.