Frequency Response Optimization of Saw Filter using Canonical Genetic Algorithm

Abstract

An optimization program is employed to design the inter-digital transducer (IDT) structure of the surface acoustic wave (SAW) transducer to aim at improvement in the transducer characteristics and to improve the frequency response of SAW filter. In this paper, Genetic algorithm is used to optimize the response of a SAW filter. Then, the comparison of the response of SAW filter is done by using GA and without GA. The goal of optimization is to find best value for each variable in order to achieve minima or maxima of an objective function within the given constraints. In present study, three design variables of SAW filter i.e. number of finger pairs in input IDT (Np1), number of finger pairs in `output IDT (Np2), center to center distance between two electrodes in a finger pair (d), are optimized. After getting the optimized parameters of SAW filter, the frequency response of bandpass SAW filter is obtained, which is better as compared to the frequency response of SAW filter getting from other methods in terms of bandwidth and ripples amplitude.