Comparative study of X-parameters and nonlinear scattering functions

S-parameters have been used in analyzing linear networks for more than half a century. Despite the great success of S-parameters, they are severely limited. In fact in real world, all systems are nonlinear. It's a hard work to characterizing the nonlinear network and thus it becomes a hot issue today. This article introduces two methods of nonlinear modeling, X-parameters and scattering functions. We give a conclusion on the relation of these two methods after comparing their basic concept and extraction systems. At the end of this paper, we present an extraction system which can adopt either X-parameters or Scattering functions for the nonlinear characterizing and modeling.