Nearly noise-free transistor operated in the 2-18 GHz range

Temperature dependent measurements of the noise parameters of a pseudomorphic high electron mobility transistor show the minimum noise figure vanishes at low temperatures for frequencies from 2 GHz up to 18 GHz and for most currents. We propose that the exponential decrease seen in the noise figure with temperature is due to a reduction of thermally activated noise sources with an activation energy of similar to 95 meV. Other noise-parameter data suggest a flattening of the noise figure paraboloid as temperature is decreased. These results demonstrate the feasibility of designing a near 0.1 dB noise figure amplifier for high-frequency operation over a wide range of currents. (C) 1998 American Institute of Physics.