Scattering- and mixed-matrix analysis of BAW devices

Bulk acoustic wave (BAW) transducers have been employed for fluid and solid property measurements as well as for signal processing applications for many years. BAW measurement and signal processing techniques are robust and miniature, making them ideal for industrial and military applications. Several structures have been considered, including resonators, delay lines and hydrophones. All of these BAW transducer geometries require an accurate and efficient analytical model of the piezoelectric plate and associated bonding, backing, electrode and sample media. Previously, lumped element models, impedance matrix and hybrid matrix analysis have been utilized. The current work details a scattering matrix analysis of multilayered BAW transducers which is rigorously derived from the wave equation and the coupled mode differential equations. It agrees well with the previous methods while allowing additional insight into the problem