COMPENSATION FOR DIFFRACTION IN SAW FILTERS.

Recent fast methods for the calculation of Fresnel diffraction assuming ″paraboilic″ anisotropy allow iterative algorithms to be practical for optimizing the response. These methods are utilized in an iterative correction method which improves the frequency response by matching bandlimited responses in the time domain. Trial example designs which initially had severe errors due to diffraction were greatly improved by corrections obtained using this algorithm, whereas the degree of correction achieved using the center frequency method was much less. Both tap position and amplitude corrections are found to be necessary.