Strontium titanate thin films for tunable YBa/sub 2/Cu/sub 3/O/sub 7/ microwave filters

Tunable ferroelectric thin films such as SrTiO/sub 3/ (STO) are promising for a variety of rf applications requiring tunability. We describe the growth and characterization of STO thin films including their dielectric properties, and summarize attempts at reducing the loss tangent of these films. We also discuss their integration with high-temperature superconductor (HTS) microwave filters for trimming purposes.