Patent ID: 7449812

Claim:
An electroacoustic transducer comprising: a first electrode having first fingers connected to a first bus bar; a second electrode having second fingers connected to a second bus bar, wherein the first and second fingers interdigitate; an active region and edge regions, the edge regions being between the active region and one of the bus bars; wherein at least one end of each of the first and second fingers abuts at least one of plural gaps; and at least one floating metal structure in each of the gaps; wherein an acoustic wave of wavelength λ is excitable at a resonant frequency, the acoustic wave having a longitudinal and a transverse excitation profile and a longitudinal and a transverse energy density profile, the longitudinal excitation profile being approximately constant and different from the longitudinal energy density profile, and the transverse excitation profile substantially corresponding to the transverse energy density profile; wherein the active region has a transverse length W, where W is at least 3λ; wherein an edge region has a transverse length D, where λ<D<W; and wherein transverse positions of the gaps relative to a bus bar vary in order to obtain the transverse excitation profile.