Response time and power handling capability of tunable microwave devices using ferroelectric films

The microwave (MW) performance of tunable stripline resonators with ferroelectric (SrTiO3 or (Ba, Sr)TiO3) planar capacitors under exposure to high voltage video pulses and MW (10 GHz) signals are studied. The resonator switching times were less than 30 nanoseconds, and these values were limited by the measurement apparatus. The dependence of film capacitance and MW loss in ferroelectric films as a function of MW signal level, and their variation during the pulse, were measured. The large signal MW dielectric constant and loss tangent varied by less than 10% with increasing MW voltage amplitude for MW field strengths up to 1 MV/m in SrTiO3 films, and 0.5 MV/m in (Ba, Sr)TiO3 films.