Frequency-Domain Models for Nonlinear Microwave Devices Based on Large-Signal Measurements

In this paper, we introduce nonlinear large-signal scattering ( [Formula: see text]) parameters, a new type of frequency-domain mapping that relates incident and reflected signals. We present a general form of nonlinear large-signal [Formula: see text]-parameters and show that they reduce to classic [Formula: see text]-parameters in the absence of nonlinearities. Nonlinear large-signal impedance ( [Formula: see text]) and admittance ( [Formula: see text]) parameters are also introduced, and equations relating the different representations are derived. We illustrate how nonlinear large-signal [Formula: see text]-parameters can be used as a tool in the design process of a nonlinear circuit, specifically a single-diode 1 GHz frequency-doubler. For the case where a nonlinear model is not readily available, we developed a method of extracting nonlinear large-signal [Formula: see text]-parameters obtained with artificial neural network models trained with multiple measurements made by a nonlinear vector network analyzer equipped with two sources. Finally, nonlinear large-signal [Formula: see text]-parameters are compared to another form of nonlinear mapping, known as nonlinear scattering functions. The nonlinear large-signal [Formula: see text]-parameters are shown to be more general.