An automatic tuning method for bandpass cavity filter based on stepping search algorithm

This paper presents an automatic tuning method based on a stepping search algorithm for bandpass cavity filters. This method imitates human tuning manipulation without recourse to a theoretical model of filter. To a certain extent, this implementation can replace and optimize the tuning work rely on engineers’ experience. The return loss and insert loss are the key indexes to measure whether the tuning terminated, and the hierarchical optimization objectives used as evaluation function of the method. To verify this approach, two screw- tuned cavity filters tuning instance are given with five screws and eleven screws respectively.