Low Loss Ferroelectric Material Development for Accelerator Applications

75565-Ferroelectric materials based on BST (barium strontium titanate) could be used as the basis for new advanced-technology microwave and particle accelerator devices. In particular, the electronic properties of this material allow one to create an X-band high-power radio frequency (rf) switch with sufficient peak power for use in linear collider rf systems. This project will develop a new BST material with a permittivity of ~500 and a loss factor of 1¿10-3 at 11.4 GHz. In addition, a process for sintering and forming large sized objects (required for phase shifter components) made of BST ceramic will be demonstrated. In Phase I, a BST-based bulk ferroelectric with permittivity of 400-500, loss factor of (3-4)?10-3 at 11.4GHz, and tunability of 15-20% at 5 V/?m bias field will be developed. The phase composition and structure of the BST samples will be studied as a function of the solid-solution composition, raw materials, and synthesis techniques. The dielectric response of the material in the (3-12) GHz and 35 GHz frequency ranges will be demonstrated. Commercial Applications and Other Benefits as described by the awardee: The ferroelectric-based tunable device technology should have application to a variety of other high-frequency, large-signal devices. Tunable devices made using bulk and thin-film ferroelectric technology also have many potential applications for the military and wireless communication industries.