An improved small-signal model for GaN HEMTs devices

An improved small-signal model applied to GaN-based devices is presented in this article. The extrinsic elements of the equivalent circuit topology are extracted using the test structures and the cut-off method. In order to obtain a good agreement between model simulations and measurements, distributed capacitive effects are taken into account. In addition, an inductance L_ds is introduced based on the conventional intrinsic equivalent circuit topology. Good agreement between the modeled and measured S-parameters is obtained for GaN HEMTs with a gate width of 2 × 100 μm (number of gate fingers × unit gate width) in the frequency range of 0.5–40 GHz.