Intrinsically switchable ferroelectric bulk acoustic wave filters based on barium strontium titanate thin films

Single-standard wireless transceivers are of limited use as multi-mode devices become ubiquitous. Adaptive and reconfigurable RF circuits are necessary to decrease size, cost, and power consumption as well as increase reliability and robustness of wireless devices. In this paper, the design, fabrication, and performance of acoustically coupled and electrically coupled filters based on the ferroelectric barium strontium titanate are discussed. In their off state, the input and output ports are isolated from one another. When switched on with the application of a dc bias voltage, a bandpass filter response is obtained.