Bulk acoustic wave coupled resonator filters

Coupled Resonator Filters (CRF) are a new form of bulk acoustic wave device that involves the vertical stacking of resonators. In that regard, the CRF can be thought of as a variation on the better known Stacked Crystal Filter (SCF). However, the CRF is actually somewhat more analogous the Monolithic Crystal Filter (MCF) that was a mainstay in filters for low frequency applications. This paper will review coupled resonator concepts, briefly including the MCF, describe the design and modeling of CRFs, and present representative experimental results.