Centimeter Waves

radio waves having a wavelength λ between 1 and 10 cm (a frequency between 30 and 3 gigahertz). They pass through the earth’s atmosphere with little distortion. Absorption of centimeter waves in the troposphere by water vapor and raindrops is substantial only for waves with λ < 3 cm, and the ionosphere is practically transparent for these waves. Centimeter waves can therefore be used for the operation of communications satellites and communications links between the earth and outer space (seeSPACE COMMUNICATIONS). Under terrestrial conditions, centimeter waves propagate within line-of-sight limits. They can propagate over greater distances by being scattered from inhomogeneities in the troposphere (seeRADIO-WAVE PROPAGATION).