Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published September 2013 | public
Journal Article

Noise Measurements of Discrete HEMT Transistors and Application to Wideband Very Low-Noise Amplifiers


The noise models of InP and GaAs HEMTs are compared with measurements at both 300 and 20 K. The critical parameter, T_(drain), in the Pospieszalski noise model is determined as a function of drain current by measurements of the 1-GHz noise of discrete transistors with 50-Ω generator impedance. The dc I-V for the transistors under test are presented and effects of impact-ionization are noted. InP devices with both 100% and 75% indium mole fraction in channel are included. Examples of the design and measurement of very wideband low-noise amplifiers (LNAs) using the tested transistors are presented. At 20-K physical temperature the GaAs LNA achieves <10-K noise over the 0.7-16-GHz range with 16 mW of power and an InP LNA measures <20-K noise over the 6-50-GHz range with 30 mW of power.

Additional Information

© 2013 IEEE. Manuscript received January 29, 2013; revised June 18, 2013; accepted June 20, 2013. Date of publication July 23, 2013; date of current version August 30, 2013. The authors would like to express their deep gratitude to S. Smith, California Institute of Technology, Pasadena, CA, USA, for the many helpful discussions, and to H. Navarette, also with the California Institute of Technology, for his help in assembly of the packaged MMICs and discrete devices.

Additional details

August 22, 2023
October 17, 2023