SVD-based reduced-order rational approximation on specific frequency bandwidth

This paper presents a model order reduction (MOR) technique, based on singular value decomposition (SVD), for rational approximations on a specific frequency range. The proposed method initially adopts a rational approximation, expressed as a set of partial fractions, obtained by the vector fitting (VF) software tool for a typically wide frequency range. Subsequently, it obtains a subset of poles within a specific narrow frequency range, either low- or high-frequency, via SVD-based truncation. This results in a reduced-order model accurate within the specific frequency range. Two examples, in which the proposed method is applied separately to low- and high-frequency ranges, are presented. The resulting reduced-order models are then used to simulate electromagnetic transients.