20 GHz tunable filter based on ferroelectric (Ba,Sr)TiO ₃ film varactors

Abstract

The tunability and dielectric losses of ferroelectric (Ba,Sr)TiO3 film varactors were measured under DC voltage at microwave frequencies (~20 GHz). A new microwave two-pole tunable waveguide filter containing four ferroelectric (Ba,Sr)TiO3 film varactors was designed and tested. The frequency tuning of the filter results from the variation in capacitance of ferroelectric varactors with DC controlling voltage.