Shear horizontal acoustic surface shape resonances

We have calculated the discrete frequencies of the elastic vibration modes localized in the vicinity of a rectangular ridge fabricated from one material that is bonded to the planar surface of a substrate of a second material. These acoustic surface shape resonances correspond to a displacement field that is polarized parallel to the ridge (i.e., it has shear horizontal polarization). The frequencies of these modes are complex because the range in which they occur overlaps the continuum of frequencies of the bulk and surface modes of the substrate, so that they can radiate energy into the latter. The modes are damped thereby, and this damping depends sensitively on the aspect ratio of the ridge and on the material parameters of the ridge and substrate.