A novel and efficient impedance matching technique based on fragment discrete structure and genetic algorithm

Abstract

This paper proposes a novel and efficient design technique to achieve multifrequency impedance matching. The matching network is mainly constructed based on fragment discrete structure, which consists of regularly distributed metallic microstrip stubs, where some of them are connected whereas others are not. Different designs are generated by determining the interconnections between each two stubs. To facilitate the design procedure, a theory based on port impedance substitution is rigorously developed to calculate the resulted performance (reflection coefficient) of each design. Finally, the optimal design is obtained by using the derived formulas and genetic algorithm. The full optimization procedure is totally free of electromagnetic (EM) simulation and is quite timesaving. Three different examples of mismatched frequency-varying complex load are adopted to illustrate the steps and functionality of the proposed method. The accuracy of the proposed fast-calculation method is also verified by EM simulation and experimental results.