MODELING OF THE IMPULSE-RESPONSE IN SAW TRANSDUCERS

Based on equations for wave propagation on YZ LiNbO3 an analytical approximation for the iumpulse response of SAW transducers is derived. It is shown that for weak piezoelectrics, corresponding to “in-line” circuit model, the impulse response carries the image of the longitudinal electric field. In strong piezoelectrics, corresponding to “crossed-field” model, the impulse response carries the image of the partial potential associated with the normal component of the electric field. Using Poynting's theorem and results from the field theory of interdigital transducers the radiation conductance and susceptance were found without a use of Mason's model. Then, it is shown that only the “crossed-field” model can be represented with ðŗ¿ functions of constant magnitude, while the “in-line” model requires exponentially growing functions. All the physical constants have been evaluated and the f3/2 frequency dependence independently confirmed. Copyright © 1979 by The Institute of Electrical and Electronics Engineers, Inc.