A surface micromachined electrostatically tunable film bulk acoustic resonator

The design, modeling, fabrication and characterization of a film bulk acoustic resonator (FBAR) that allows frequency tuning by MEMS actuation are reported. FBARs are micromachined versions of bulk acoustic wave (BAW) resonators working in the microwave regime. A small range of frequency tuning is desired to cope with drifts from different origins. In conventional approaches, this functionality has been realized by introducing a discrete element. In this paper, a different design is proposed, in which the MEMS tuning element is integrated in the FBAR structure and tuning is realized by electrostatic actuation. A first demonstration of frequency tuning is also presented.