This conference proceedings appears in: Lecture Notes in Engineering and Computer Science. Open-access online version: http://www.iaeng.org/publication/IMECS2010/Vector Fitting (VF) has been applied to reformulate traditional system identification techniques by introducing a partial-fraction basis to avoid ill-conditioned calculation in broadband system identifications. Because of the reliable and versatility of VF, many extensions and applications have been proposed, for example, the macromodeling of linear structures in signal/power integrity analyses. In this paper, we discuss the macromodeling framework and some main features in VF in terms of data, algorithms and models. Finally, an alternative P-norm approximation criterion is proposed to enhance the macromodeling process.postprintThe International MultiConference of Engineers and Computer Scientists (IMECS 2010), Hong Kong, 17-19 March 2010. In Proceedings of the International MultiConference of Engineers and Computer Scientists, 2010, v. 2, p. 1407-141