Analysis of the Gate Current’s Influence on the RF Power Performance of InAlN/GaN HEMTs

IEEE Transactions on Microwave Theory and Techniques, Vol. 73, No. 2, Aug. 2024

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Gate current is known to limit device performance, yet a detailed analysis of its impact on RF power performance has not been extensively documented. This article examines the influence of gate current on RF power performance. A small-signal equivalent-circuit analysis shows that gate current degrades the device’s RF power performance, with higher gate currents causing greater degradation. In addition, the effect of gate current varies with frequency due to the frequency-dependent impedance of $C_{gs}$ and $C_{gd}$, resulting in more significant degradation at lower frequencies because of the parallel connection of gate conduction with these capacitors. These findings are validated under large-signal conditions using an experimentally verified device model for InAlN/GaN high-electron-mobility transistors (HEMTs).