Noise Characteristics of Millimeter-Vave HEMT Amplifiers

Extensive measurements of the noise properties of a low-noise mm-wave HEMT amplifier are carried out, as a function of the dc operating point of the active devices. These are used to determine the bias-dependence of the noise characteristics, and the relationship between the associated power gain and the maximum power gain. The results provide an estimate of the bias sensitivity of the amplifier performance at the low-noise operating point, and establish a quantitative trade-off between input port matching for minimum noise figure and for maximum power gain.