Skip to Main Content
A new concept for the low-frequency dispersion aspect of large-signal modeling of microwave III-V field-effect transistors is presented. The approach circumvents the integrability problem between the small-signal transconductance GmRF and the output conductance GdsRF by means of an integral formulation and simultaneously yields a proper description of the drain channel current in the small- and large-signal regime. In the theoretical description of the approach and in an extraction example of an AlGaN/GaN HEMT, it is shown that three independent 2-D nonlinear quantities determine the intrinsic drain channel current (GmRF, GdsRF, and dc current). The concept is transferred to the modeling of the nonlinear charge control, where the integrability problem between the large-signal charge functions and the small-signal intrinsic capacitance matrix (Cgs, Cgd, and Cds) is addressed consistently under consideration of the charge control delays. For the large-signal modeling under pulsed-dc/RF excitation, the dc continuous wave (dc-CW) modeling approach is combined with the state-modeling concept using a superposition formula for drain current and charges, respectively. The new model is implemented in ADS using a 12- and 14-port symbolically defined device for both the dc-CW and pulsed-RF case, respectively. The model has been verified by comparison to measured CW and pulsed-RF load-pull and waveform data at 10-GHz fundamental frequency.