Kink Effect in ${\rm S}_{22}$ for GaN and GaAs HEMTs

This letter provides a clear understanding of the kink effect in S22for active solid-state electronic devices. The origin of the kink effect is ascribed to the intrinsic section of the transistor, whereas the extrinsic elements determine its shape at the extrinsic ports. Therefore, to fairly compare the kink effect for GaN and GaAs HEMTs, the present analysis is not only focused on the whole devices but also on their intrinsic sections. The experimental evidence shows that, independently of the specific semiconductor technology, the size and the frequency band of the kink effect are mainly due to the values of the intrinsic transconductance and capacitances, respectively.