The application of pseudoinverse matrices for diffraction calculation of SAW propagation in transducers

The design of narrowband SAW filters involves the calculation of SAW propagation in transducers which are long compared to the square of their apertures in wavelengths. To increase design accuracy, it is of high importance to model diffraction effects in these transducer structures. We present a method for calculating diffraction of both forward and backward propagating SAWs, which are coupled. Hence, both SPUDT filters and inline resonator filters can be described by diffraction. The simulation of diffraction is performed by dividing the transducers into tracks (across the transducers´ aperture) as for the analysis of apodized weighted transducers. By allowing for a direct acoustic coupling between the tracks, we simulate diffraction by a coupling theory. This theory is capable of describing the transducers by a uniform surface condition diffraction theory or as waveguides