The microwave (similar to 10 GHz) performance of a tunable resonator employ
ing ferroelectric (Ba,Sr)TiO3 film planar varactors under exposure to high
levels of microwave power was studied. The nonlinear characteristics of the
ferroelectric films affected by the large signal microwave electrical fiel
d were evaluated. The limitations of high power performance for the films a
nd tunable microwave devices based on the films were established.