Using Orthogonal Polynomials as Alternative for VIOMAP to Model Hardly Nonlinear Devices

Being a series approximation, VIOMAP is not well suited to model hardly nonlinear devices due to numerical problems. The prediction of two-tone behavior based on one-tone measurements of a microwave power amplifier which is driven deeply into compression, is used as test case to show the potentials of a possible alternative which is based on orthogonal polynomials.