Loewner matrix approach for circuit modelling in FEM analysis of microwave filters

A circuit description of the electromagnetic behavior in microwave filters by means of the data provided by FEM analysis in the frequency band of interest is detailed. Loewner matrix approach is used to carry out a tangential interpolation of the simulation data, giving rise to a linear dynamical system description fitting the simulation results. The FEM solver is then used as a black box unlike other model-order reduction techniques. As a result, from this linear dynamical system, a transversal coupling matrix gathering all electromagnetic phenomena within a frequency band is found.