Frequency-Domain Fitting Techniques: A Review

This paper presents a theoretical review and comparisons between vector fitting, matrix-pencil-method, and Loewner matrix techniques for the fitting of frequency-domain functions. Firstly, the theoretical fundaments of each technique are briefly reviewed. Secondly, their computational performances and fitting accuracy are compared through different case studies. As for Loewner Matrix method, a novel implementation is proposed for a fair comparison with the other two techniques. Moreover, it is demonstrated that this novel implementation has some advantages over the traditional one. Finally, global remarks and recommendations are specified to take advantage of the capabilities exhibited by each technique.