A nonlinear distributed FET-model, for millimeter-wave circuit design by harmonic balance techniques

A systematic procedure is proposed for deriving a nonlinear, distributed FET model that can be implemented in harmonic balance simulators for nonlinear design at millimeter waves. The model is derived from the knowledge of the conventional lumped nonlinear equivalent circuit and the geometrical dimensions of the FET. A FET-finger is modeled by N sliced sections. Each section includes a nonlinear two-port, inserted between two linear four-ports. Element values of the nonlinear two-port are derived from the lumped model by appropriate scaling rules. Element values of the linear four-port are derived from an electromagnetic analysis of the transverse structure of the FET, taking into account coupling and distributed effects along the electrodes. The model is applied to the nonlinear analysis of a millimeter-wave FET.<>