Fuzzy models for quasi-static calculations of single ground plane coupled CPW by CADMFILT software

Abstract

In this paper, two new subdesign tools including the quasi-static and fuzzy model calculations for the electrical parameters of the coupled planar transmission lines used in the design of microwave communication subsystems including resonators, filters, and multiplexers are presented for CADMFILT software. Proposed subdesign tools have properties such as electrical parameter calculations for microwave circuit analysis/synthesis, fuzzy logic model applications, comparisons, and graphical demonstrations. The first subdesign tool can calculate the electrical parameters of the coupled planar transmission lines by using the quasi-static analysis method. The other tool is based on subtractive fuzzy clustering, which can offer approximate solutions as an alternative to numerical and analytical closed-form expressions of quasi-static analysis. The proposed subdesign tools have a competent and efficient algorithm to provide fast, accurate, and sensitive results. To test the accuracy of these tools, a coupled coplanar waveguide with a single ground plane structure has been performed. The results obtained from the subdesign tools for both approaches have been compared. The proposed fuzzy logic models use the electrical parameters calculated from the quasi-static analysis as training and control data files. The accuracy of each model has been tested by error analysis and the validity of the model results has been demonstrated by comparing them with the results of the quasi-static approach. It is expected that the developed efficient, fast, and versatile subdesign tools will help researchers to simplify their designs by providing a control mechanism in the RF/microwave circuit design processes.