Millimeter-wave low-noise amplifiers-an overview

The contributions to system noise, including those external to the receiving system, are discussed, with emphasis on the 30-100-GHz range and the latest results obtained with high-electron-mobility transistors (HEMTs). The different types of HEMTs are defined, and a table showing the achievable noise figures of multistage low-noise amplifiers as a function of frequency is presented. An example of a state-of-the-art 43-GHz HEMT amplifier operating at a temperature of 17 K is presented.<
>