Switchable dual-frequency barium strontium titanate film bulk acoustic resonators

Abstract

Innovative frequency selective microwave circuit designs are needed to reduce complexity, size, and cost of multi-standard transceivers. Here, the electric field induced piezoelectricity and electric field dependent permittivity of barium strontium titanate are utilized to design multi-frequency intrinsically switchable film bulk acoustic resonators. Individual resonators with different resonance frequencies are switched on and off by controlling the dc bias voltage applied across their terminals. A switchable dual-frequency resonator consisting of series connected 0.95 GHz and 1.15 GHz resonators is demonstrated. The small size and simple design of multi-frequency BST resonators are attractive for use in oscillators and filters for adaptive and reconfigurable radios.