Stopband characteristics of shallow gratings

Abstract

A numerical method of rapidly computing the width of the stopband of a shallow grating in a SAW filter and the dependence of this bandwidth on fabrication parameters is presented. The method is based on the properties of the equivalent circuit of the unit cell at the transition frequencies. Numerical results illustrate the variation of the relative bandwidth with respect to the element reflection coefficient, the mark-to-space ratio, and the velocity perturbation parameter.