Extremely high frequency (EHF) is the ITU designation for the band of radio frequencies in the electromagnetic spectrum from 30 to 300 gigahertz, above which electromagnetic radiation is considered to be low (or far) infrared light, also referred to as terahertz radiation. Radio waves in this band have wavelengths from ten to one millimetre, giving it the name millimetre band or millimetre wave, sometimes abbreviated MMW or mmW.