A time domain diffraction analysis for SAW transducers

A time domain diffraction analysis for surface acoustic wave (SAW) transducers was previously developed based on Huygen´s principle. The analysis was performed using an approximation to the scalar two dimensional impulse response of an ideal point source which allowed for fast computation of diffraction effects in the time domain. Because the diffraction analysis was performed in the time domain a broadband frequency prediction of diffraction effects via the Fourier transform was possible. This paper presents a more rigorous derivation of the time domain impulse response from the angular spectrum of waves (ASoW) approach for the case of isotropic velocity. The extension of the analysis to include the velocity and electromechanical coupling anisotropy found in typical SAW substrates is also presented. Predictions of broadband diffraction effects are shown for several representative SAW transducers