Design Of Filters Based On Space Mapping Technique

With the rapid development of wireless communication technology, and various new wireless communication system emerged, which stimulated microwave active and passive components of rapid development,also to filter performance put forward higher request.In the design phase of the microwave filters, due to the commercial EM(electromagnetic) simulator which takes time cost huge, the simulation and optimization of the whole filter is a very complex process. The method of space mapping is just proposed for the defect of the EM simulator. In this paper, a lot of work in the application of the method of space mapping in filter design. Gives a detailed design examples including microstrip filter, coaxial cavity filter and tubular filter. These methods can as a reference for the engineering application.This paper is divided into five chapters, the first chapter mainly introduces the subject background and meaning, and the main work of this paper. The second chapter mainly introduces two kinds of the space mapping method that most commonly used, the aggressive space mapping and the implicit space mapping. Give their procedures of this algorithm, and give the design example of microstrip filter to illustrate the application of these method respectively. The third chapter mainly discusses the aggressive space mapping in coaxial cavity filter design. In the parameter extraction stage, introduces two parameter extraction methods, "the equivalent circuit optimization method" and "Cauchy method", and each of them have their design example. Then take the Cauchy method extend to extracting the diplexer polynomial, the design example shows that this method is effective. The fourth chapter mainly introduces the design method of tubular filter, firstly gives the physical realization of the equivalent lumped element of the tubular filter, then summed up the synthesis method narrow-band tubular filter, detailed discuss the space mapping method in tubular filter design, the fine model dimension of the each iteration is obtained from the empirical formula. Finally, detailed introduces the curve-fitting method in wide band filter design. The main idea of this method is split and approximation, According to the curve-fitting comparison method between circuit simulation and EM simulation results, the mapping relationship between element dimension and its equivalent circuit is obtained, this is just the extend application of the method of space mapping. The design example shows this method is effective. The work of this paper are summarized in the last chapter, and puts forward the next job prospects.