Universal Method for Compensation of SAW Diffraction and Other Second Order Effects

Abstract

All known methods for diffraction compensation replace the unapodized transducer by a single tap. T his assumption neglects variations of the SAW beam profile over the length of the unapodized transducer and leads to unsatisfying results of the compensation procedure in many cases of interest. Our compensation algorithm computes corrections to the taps of the apodized transducer from the deviations of the analysed frequency r esponse (including second order effects) from the desired response, using a quasi-Newton-opt imization method which takes the unapodized transducer into consideration. This method was successfully applied to remove diffraction e ffects from analysed and measured frequency r esponses, however, the same method can be applied to other second order effects as well.