Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Noise-Temperature Measurement System for the WR-28 Band



James P. Randa, L. A. Terrell


The NIST Noise Project has constructed and tested a radiometer for the measurement of noise sources in the WR-28 waveguide band (26.5 GHz to 40 GHz). It is a total-power radiometer which incorporates a six-port reflectometer for the measurement of relevant reflection coefficients. The radiometer is similar in design to existing NIST systems covering the WR-62 (12.4 GHz to 18 GHz) and WR-42 (18 GHz to 26.5 GHz) bands. This paper reviews the theory and describes the design, testing, and operation of the system. Because of the similarities between the present system and the existing WR-62 and WR-42 systems, much of this document also applies to those systems.
Technical Note (NIST TN) - 1395
Report Number


noise, noise measurement, noise temperature, radiometer, thermal noise


Randa, J. and Terrell, L. (1997), Noise-Temperature Measurement System for the WR-28 Band, Technical Note (NIST TN), National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed June 19, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created July 31, 1997, Updated October 12, 2021