A nonlinear charge model for RF power FETs is presented. The model, intende
d for use in harmonic-balance simulators, calculates the time evolution of
the nonlinear charge in a period of the steady-state regime. For that, the
experimentally extracted capacitances are integrated using the device dynam
ic load cycle as integration path. The proposed approach is technology inde
pendent and it has been applied here to a Si LDMOSFET and a SiC MESFET. Loa
d pull measurements have been performed to verify the validity of the model
.