Abstract
In order to increase the reliability of Surface Acoustic Wave (SAW) filters, a robust optimum design technique is presented. The frequency response characteristics of SAW filters are governed primarily by their geometrical structures, i.e., the configurations of Interdigital Transducers (IDTs) and reflectors fabricated on piezoelectric substrates. For deciding desirable structures of SAW filters through the computer simulation, conventional design techniques utilize the equivalent circuit model of IDT. However, they have rarely considered the accuracy of the underlying model that may be spoiled by the dispersion of circuit parameters. In this paper, considering the errors of these parameters, the robust optimum design of SAW filters is formulated as a constrained optimization problem. Then, a penalty function method combined with an improved variable neighborhood search is proposed and applied to the problem. Computational experiments conducted on a practical design of a resonator type SAW filter demonstrate the usefulness of the proposed method.
