The Q band is mainly used for satellite communications, terrestrial microwave communications and for radio astronomy studies such as the QUIET telescope. It is also used in automotive radar, and radar investigating the properties of the Earth's surface
The microwave spectrum is usually defined as electromagnetic energy ranging from approximately 1 GHz to 100 GHz in frequency, but older usage includes lower frequencies. Most common applications are within the 1 to 40 GHz range. Microwave frequency bands, as defined by the Radio Society of Great Britain (RSGB), are shown in the table below:
Footnote: P band is sometimes incorrectly used for Ku Band. "P" for "previous" was a radar band used in the UK ranging from 250 to 500 MHz and now obsolete per IEEE Std 521, see  and . For other definitions see Letter Designations of Microwave Bands
^Atanassov, VB and Balan, MG and Haimov, SJ and Kulemin, GP and Michalev, MA and Mladenov, L.H. and Pedenko, Y.A. and Razskazovsky, VB and Savchenko, AK and Vasilev, VL (1990). "Experimental study of nonstationary X-and Q-band radar backscattering from the sea surface". Radar and Signal Processing, IEE Proceedings F137 (2): 118–124. doi:10.1049/ip-f-2.1990.0017.