Millimeter-wave low-noise high electron mobility transistors

High electron mobility transistors (HEMT's) have been fabricated which demonstrate excellent millimeter-wave performance. A maximum extrinsic transconductance as high as 430 mS/mm, corresponding to an intrinsic transconductance of 580 mS/mm, was observed in these transistors. A unity current gain cutoff frequency fTas high as 80 GHz and a maximum frequency of oscillationfₘₐₓof 120 GHz were projected for these HEMT's. At 40 GHz, a minimum noise figure of 2.1 dB with an associated gain of 7.0 dB has also been measured. These are the highestfT, fₘₐₓ, and the best noise performance reported to date. The results clearly demonstrate the potential of HEMT's for millimeter-wave low-noise applications.