A Comparison of Complex Curve Fitting and Subspace Identification Algorithm for Circuit Modeling Using Frequency Domain Data

Efficient transient simulation of complex structures or components characterized by frequencydomain network parameters is of great interest in microwave theory. In this paper, two different model extraction techniques for broadband linear network characterization are discussed. A parametric complex curve fitting technique and a frequency-domain subspace identification algorithm are applied to generate passive circuit models for microwave devices characterized by measured frequency-domain port response data. By means of practical examples both methods are evaluated regarding usability, accuracy and CPU time.