Rapid design optimization of microwave filters using variable-fidelity EM simulations and adjoint sensitivity

A simple yet robust and computationally efficient methodology for design optimization of microwave filters is presented. The proposed algorithm exploits variable-fidelity electromagnetic (EM) simulation models and adjoint sensitivities for fast evaluation of EM model response derivatives. Most of the operations are performed on the low-fidelity EM model, whose correction is realized by means of space mapping (SM). In the optimization process, the SM parameters are optimized together with the design itself, which allows us to keep the number of both low- and high-fidelity simulations at low levels. The operation and performance of the method is demonstrated using two examples of waveguide filters.