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.

Small-Scale Fading

The constructive and destructive interference gives rise to a phenomenon known as small-scale fading, where the strength of a received signal can fluctuate up to tens of dBs over the small-scale distance of just wavelengths. NIST is one of the three organizations worldwide – to our knowledge – that has taken high-precision measurements for fading at mmWave frequencies. Our measurements indeed show that the fading is weaker, as evidenced by the longer correlation distance – the distance over which the channel can be considered stationary. In addition, we have been able to demonstrate the dependence of correlation distance on beamwidth.


Beamwidth-dependent correlation distance in our Laboratory environment: scenario map (left) and results from measurements (right). As the beamwidth widens, more and more MPCs are admitted, increasing interference and in turn reducing the correlation distance.


Our comprehensive evaluation of the impact of beamwidth on correlation distance can be found in the reference below:

[1] A. Hughes, S. Y. Jun, C. Gentile, D. Caudill, J. Chuang, J. Senic, and D. G. Michelson, “Measuring the Impact of Beamwidth on the Correlation Distance of 60 GHz Indoor and Outdoor Channels,” IEEE Open Journal of Vehicular Technology, vol. 2, pp. 180-193, March 2021.


Radio Access and Propagation Metrology Group

Created September 28, 2021, Updated September 29, 2021