5. Conclusion

In this article, an extension of S-parameters for the characterization of non-linear devices has been presented. Unlike linear devices, non-linear devices cannot be described by their S-parameters, as the superposition principle cannot be applied due to the device's non-linear behavior. In fact, the definition of S-parameters can be generalized to allow the characterization of devices with non-linear behavior. A model has been presented in this article in which the nonlinear response is linearized around a single harmonic component of the input signal, i.e. the fundamental input component. A frequency-domain analysis of the small-signal responses to the various harmonics can then be used to translate and analyze the device's nonlinear behavior.

To illustrate this methodology, the X-parameter formulation was presented, among others, as an extension of the classical...