A joint field/circuit design model of microstrip ring dual-mode filter: theory and experiments

A unique CAD-oriented joint field/circuit model is developed for the accurate and efficient design of a class of microstrip ring dual-mode filters. The field model is used to extract lumped circuit elements of layout discontinuities while the circuit model presents a unified equivalent network characterizing the filter topology. This is achieved by applying our recently proposed “short-open calibration” (SOC) technique in the method of moments (MoM) algorithm. Two types of stub-loaded microstrip ring dual-mode filters are studied in detail and designed with the proposed design technique. It is shown that the design results on the basis of the proposed joint model are in agreement with our experiments