Automatic and multithreaded method for determining the number of vector fitting poles based on empirical data

Abstract

AbstractThe vector fitting method has been largely used to generate accurate and passive time‐domain macromodels for circuits or structures characterized by frequency‐domain data such as scattering parameters. Nevertheless, very few approaches to determine the vector fitting order were discussed in the literature. In this paper, an iterative method to automatically identify the number of vector fitting poles is proposed. It can achieve acceptable performance and accuracy by capitalizing on the fact that the number of vector fitting poles lies in the range that spans the number of resonance peaks in the model and double that number as deduced from the empirical data that was acquired by experimentation on different types of models. Therefore, the algorithm's awareness of the frequency response of the model and confining the search for an acceptable order within the aforementioned range proved to be key factors to enable it to mostly outperform its MATLAB counterpart as shown in the experimental results. Furthermore, a multithreaded implementation of the proposed method is introduced to distribute the vector fitting passes on multicore processors in order to obtain a better speedup factor. The experiments that demonstrate the positive effect of the multithreaded version on performance are also presented.