In this article, we have presented the effect of low gate bias on short circuit current gain h 21 beyond cutoff frequency in AlGaN/GaN HEMT. A small-signal model, based on its intrinsic and extrinsic parameter values, is simulated beyond the cutoff frequency to analyze its peak. From the study, it has been observed that the first peak of short circuit current gain has the resonance frequency as well as magnitude variation with respect to low gate voltages. Whereas, the second peak of the current gain h 21 has only magnitude dependency on low gate voltage with fixed resonance frequency. The relevance of this study is to provide a comprehensive insight to the circuit designer to efficiently consider these windows of current gain peak beyond the cutoff frequency into their design. For this analysis, we have taken AlGaN/GaN HEMT device with a channel length of 0.8 μm and 2× 200 μm 2 gate width. A measured S-parameter data up to 40 GHz at low gate bias is used to extract the model parameters.