Intelligence method for optimizing a microstrip filter based on folded dual-mode resonators

An efficient method for optimizing microwave filters based on dual-mode resonators has been developed. In this method, a prior knowledge of how the passband parameters depend on the resonators’ resonant frequencies and couplings is used. It is shown that the rules for the intelligence optimization of filters, previously formulated for single-mode resonators, can also be applied to dual-mode resonators. To this end, each dual-mode resonator of the filter should be put into correspondence with its proper pair of imaginary single-mode resonators whose coupled-oscillation frequencies coincide with the frequencies of the dual-mode resonator.