AlGaN/GaN HEMT‐based fully monolithic X‐band low noise amplifier

A fully monolithic AlGaN/GaN HEMT‐based low noise amplifier is reported. The circuit demonstrated a noise figure of 3.5 dB, gain of 7.5 dB, input return loss of –7.5 dB, and output return loss of –15 dB at 8.5 GHz. The dc characteristics of individual 0.25‐μm × 150‐μm transistors were: maximum current density of 1.0 A/mm, maximum transconductance of 170 mS/mm and a threshold voltage of –6.8 V. The devices have a typical short circuit current gain cutoff frequency of 24.5 GHz and a maximum oscillating frequency of 48 GHz. The devices demonstrated a minimum noise figure of 1.6 dB with an associated gain of 10.6 dB at 10 GHz. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)