Construction of models of microwave transistors when changing the probing signal in the frequency and power range

It is shown that to model a transistor in the form of S-parameters in the large signal mode, it is necessary to present the model as two S-matrices that describe the transistor at two phase differences between the incident and reflected waves equal to 0 and 90 degrees. The problem of matching a transistor with a load is reduced to solving a nonlinear equation with respect to a previously unknown phase difference, after which the load impedance is selected from the complex-conjugate matching condition.