A HYBRID COMPUTER-AIDED TUNING METHOD FOR MICROWAVE FILTERS

A hybrid tuning method for microwave filters is presented in this paper. This novel tuning technique is based on the combination of the Cauchy method and aggressive space mapping (ASM) technique. Cauchy method is applied to determine the characteristic polynomials of the filterʹs response, then the parameters (coupling matrix) of the low-pass prototype is extracted from the characteristic polynomials. The aggressive space mapping is used to optimized the fine model to guarantee that each step of a tuning is always in the right direction. The validity is verified by two examples. One deals with the four-resonator cross-coupled filter and the other one is an direct coupled six-resonator filter.