Tuning method for microwave filters with different phase shift effects

A novel tuning method based on aggressive space mapping (ASM) and genetic algorithm (GA) is presented in this paper. The method is applied to microwave filters with different phase shift effects at I/O ports. The tuning direction and magnitude are predicted by ASM. The phase shift effect can be calculated by GA, then the coarse model parameters are extracted by the Cauchy method. The fine model is constructed by the commercial FEM simulation software HFSS, and the coarse model is the equivalent circuit. A sixth order cross-coupled filter tuning example is used to verify the new method and the validity of the method is proved. The filter meets specifications less than four iterations.