Modification of Scalar Potential Theory for Surface Acoustic Wave Devices to Take Slowness Asymmetry into Account

摘要

This paper discusses modification of the scalar potential (SP) theory for the analysis of surface acoustic wave (SAW) devices to take asymmetry of the SAW slowness curve into account. First, it is shown that the SP theory is equivalent to the two-dimensional wave equation for a shear-vertical bulk wave, where variation of acoustic properties is expressed as that of the mass density while the elastic properties are uniform in the structure. Then the modified boundary conditions and the mode orthogonality relations are derived from the wave equation to take the asymmetry into account.