Tunable ferroelectric thin films such as SrTiO3 (STO) are promising for a v
ariety of rf applications requiring tunability. We describe the growth and
characterization of STO thin films including their dielectric properties, a
nd we summarize attempts at reducing the loss tangent of these Rims. We als
o discuss their integration with high-temperature superconductor (HTS) micr
owave filters for trimming purposes.