Efficient implementation of the aggressive space mapping technique for microwave filter design

We propose in this paper a very efficient implementation of the Aggressive Space Mapping (ASM) technique for designing and tuning microwave filters. To illustrate the advantages introduced by the ASM that we propose, we discuss two ASM strategies using both the same commercial finite-elements software tool as the “High Accuracy” space (HA). The first one is based on the use of a classic circuit model as a “Low Accuracy” model (LA) of the filter structure, while the second one is based on a low accuracy Multimode Equivalent Network (MEN) representation of the filter structure. Our investigation shows that while the Circuit-Based ASM requires a number of iterations to reach convergence, the MEN-Based ASM converges in just one step. A justification for this very remarkable behavior is also provided in terms of perturbation theory. Finally, in addition to simulations, measured results for a four-pole filter are also presented thereby fully validating the results obtained.