Space mapping optimization of waveguide filters using finite element and mode-matching electromagnetic simulators

For the first time in design optimization of microwave circuits, the aggres sive space mapping (SM) optimization technique is applied to automatically align electromagnetic (EM) models based on hybrid mode-matching/network the ory simulations with models based on finite-element (FEM) simulations. SM o ptimization of an H-plane resonator biter with rounded corners illustrates the advantages as well as the challenges of the approach. The parameter ext raction phase of SM is given special attention. The impact of selecting res ponses and error functions on the convergence and uniqueness of parameter e xtraction is discussed. A statistical approach to parameter extraction invo lving ii and penalty concepts facilitates a key requirement by SM for uniqu eness and consistency. A multipoint parameter extraction approach to sharpe ning the solution uniqueness and improving the SM convergence is also intro duced. Once the mapping is established, the effects of manufacturing tolera nces are rapidly estimated with the FEM accuracy. SM has also been successf ully applied to optimize waveguide transformers using two hybrid mode-match ing/network theory models: a coarse model using very few modes and a fine m odel using many modes to represent discontinuities. (C) 1999 John Wiley & S ons, Inc.