The Ka band ("kay-ay band") covers the frequencies of 26.5–40 GHz,[1] i.e. wavelengths from slightly over one centimeter down to 7.5 millimeters.[2] The Ka band is part of the K band of the microwave band of the electromagnetic spectrum. This symbol refers to "K-above": in other words, the band directly above the K-band. The 30/20 GHz band is used in communications satellites, uplink in either the 27.5 GHz and 31 GHz bands,[3] and high-resolution, close-range targeting radars aboard military airplanes. Some frequencies in this radio band are used for vehicle speed detection by law enforcement.[4]Kepler Mission uses this frequency range to downlink the scientific data collected by the space telescope.
The designation "Ka-band" is from Kurz-above, which stems from the German word "kurz" meaning short.[5]
In satellite communications, the Ka band allows higher bandwidth communication. It is used in the Inmarsat I-5 system[6] and will be used in the upcoming Newsat Jabiru,[7] and Iridium Next satellite series, for instance. The Ka band is more susceptible to rain attenuation than is the Ku band, which in turn is more susceptible than the C band.[8]