Differential COM model of transducers

An accurate and numerically efficient model for transducers with non-uniformly weighted internal reflections has been developed. Unlike the conventional coupling-of-modes (COM) technique which represents a nonuniform transducer as a set of cascaded uniform sections, the new method calculates the transducer's response by solving a set of nonlinear ordinary differential equations. This approach makes the formulae for P-characteristics much simpler than the ones obtained by COM-an important feature for theoretical analysis. More important, it provides simple formulae for derivatives of the P-characteristics with respect to the reflectivity and transduction functions, which is crucial for efficient optimization of SAW designs. Numerical experiments show excellent agreement between the new "differential" COM model of transducer analysis and the conventional COM model.