On the application of model-order reduction in the fast and reliable optimization of microwave filters and diplexers

This paper discusses the application of model-order reduction in the optimization of microwave devices. It focuses on the direct optimization of the scattering matrix poles and zeros, yielding an advanced reliability and universality at a computational cost that is comparable to a surrogate model optimization. The scattering matrix poles and zeros are computed from a state-space model that is obtained from a finite-integration discretization and then optimized to match a set of target poles and zeros.