The X-band belongs to the microwave frequency range. There are two versions of X-band: one refers to the radio wave band with a frequency of 8-12 GHz, and the other refers to the frequency range of X-band with a frequency of 7-11.2 GHz.
According to IEEE 521-2002 standard, X-band refers to the radio wave band with a frequency of 8-12 GHz (wavelength range 37.50 – 25.00 mm), which belongs to microwave in the electromagnetic spectrum.
The X-band usually has a downlink frequency of 7.25-7.75GHz and an uplink frequency of 7.9-8.4GHz. It is also often referred to as the 7/8 GHz band (English: 8/7GHz X-band).
The common X-band communication frequency range of NASA and ESA deep space stations is 7145-7235MHz for uplink and 8400-8500MHz for downlink.
Some experts do not agree that 7.25-7.75GHz belongs to the X-band. They believe that it belongs to the C-band. However, many literatures and journals attribute 7.25-7.75GHz to the X-band.
According to Article 8 of the radio rules of the International Telecommunication Union, X-band is used for space research, broadcasting satellites, fixed communication service satellites, earth exploration satellites, meteorological satellites, and other purposes in space applications. Rain attenuation has certain influence on X-band signal transmission.