A simplified scattering synthesis method for LC ladder filters

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Zhou, Zhiwei
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This thesis is devoted to the presentation of a simplified synthesis method and its application in the development of a computer program for the synthesis of LC ladder networks. The approach developed in the thesis is based on scattering transfer matrix theory which does not seem to have been applied directly to ladder synthesis before. The most important part of this thesis is the determination of a scattering sy thesis strategy for choosing the sequence of transmission zeros. A synthesis strategy was developed by W. F. Gottlicher for application to the traditional synthesis procedure. Gottlicher's method, presented in his thesis, is adapted as the basis of the scattering strategy. In addition, this thesis introduces a set of simplified scattering calculations by appropriately modifying the details of Gottlicher's strategy. The simplified scattering algorithm involves only calculation of the reflectance and the delay at a transmission zero and at zero or infinity. For multiple transmission zeros at zero orinfinity, the second and third derivatives of polynomials ' g' and 'h' at zero or infinity are required in addition. The main results are given in 'Chapter 3'. In that chapter, the derivation of the scattering characterization for all of the circuits and realization details of the modified strategy are presented. In ' Chapter 4', the flowgraph of the simplified scattering LC ladder filter synthesis program together with several design examples is presented. The thesis concludes with a summary and recommendations.