The Ku band (pronounced "kay-yoo")'s a portion of the electromagnetic spectrum in the microwave range of frequencies. This symbol refers to "K-under" (in the original German, "Kurz-unten", with the same meaning)—in other words, the band directly below the K-band. In radar applications, it ranges from 12 to 18 GHz according to the formal definition of radar frequency band nomenclature in IEEE Standard 521-2002. Ku band's primarily used for satellite communications, most notably NASA's Tra… (More on Ku-band)