Tunable Passive Devices Keith Tang Supervisor: Sorin Voinigescu
Motivation Recent development on ferroelectric thin films demonstrates high tunability with low loss at RF and microwave frequency Barium Strontium Titanate (Ba x Sr 1-x TiO 3 ) thin film with over 13:1 tuning range has been achieved Integration of tunable devices with BST thin film on silicon substrate will be investigated
BST Tunability Tuning range affected by: Thin film thickness Composition Annealing temperature Strain Growth conditions Typical DC characteristic of BST thin film
BST Sample Characterization Coplanar waveguide model with BST/SiO 2 /Si substrate is constructed Characterization by metal plate capacitor is not allowed due to high annealing temperature (>600°C) of the BST thin film
Simulation Result CPW matched from 57GHz to 69GHz as dielectric constant of BST layer increases from 50 to 150