Automated EM-Based Design of Bandpass Filter by Sequential Parameter Extraction and Space Mapping Technique

A fully automated direct EM design approach for an-pole filters is proposed by integrating the reflected group delay design procedure with a novel sequential parameter extraction method. This approach contains a number of design stages in which 2-3 resonance frequencies of individual resonators or adjacent couplings are extracted from the simulated reflected group delay response of a one-port network separated from the entire filter. The space mapping technique is used to estimate geometric parameters from the extracted elements. Lagrange interpolation is exploited during the design process to estimate a few design parameters using mapping information from previous stages. A Matlab program is created to automate the design of a 6-pole interdigital microstrip band pass filter.