Enhancement of EMI Immunity of Cables using Periodical and Quasi-periodical Structures Optimized by the Genetic Algorithm

Abstract

The present work is dedicated to the problems of synthesis of stop-band structures based on non-uniform transmission lines (NTL) with parameters distributed periodically or quasi-periodically along the axial coordinate. The parameter variation is achieved by changing the structure geometry or medium properties. The subject mentioned is considered with relation to standalone filter design as well as to a problem of improving a transmission medium in such a way that this medium has properties of a stop-band filter. The problems of optimization of NTL structure are studied with the aim of obtaining maximum stop-band in the given frequency range. Based on the investigation of periodical structures the resonant conditions for different ways of parameter variation are developed. It is shown that due to changeover from the periodical structure to a quasi-periodical one it is possible in a number of cases to widen the initial stop-band obtained for the periodical structure. The genetic algorithm is used to obtain the optimal nonuniformity distribution along the line. © 2005, The Institute of Electrical Engineers of Japan. All rights reserved.