电磁波频谱如以下表格：Electromagnetic spectrumNameWavelengthFrequency (Hz)Photon energy (eV)Gamma ray< 0.02nm> 15 EHz> 62.1 keVX-ray0.01nm – 10nm30 EHz – 30 PHz124 keV – 124 eVUltraviolet10nm – 400nm30 PHz – 750 THz124 eV – 3 eVVisible light390nm – 750nm770 THz – 400 THz3.2 eV – 1.7 eVInfrared750nm – 1mm400 THz – 300GHz1.7 eV – 1.24 meVMicrowave1mm – 1m300GHz – 300MHz1.24 meV – 1.24 µeVRadio1mm – 100km300 GHz – 3 kHz1.24 µeV – 12.4 feVMicrowaves travel solely by line-of-sight paths; unlike lower frequency radio waves, they do not travel as ground waves which follow the contour of the Earth, or reflect off the ionosphere (skywaves). Although at the low end of the band they can pass through building walls enough for useful reception, usually rights of way cleared to the first Fresnel zone are required. Therefore, on the surface of the Earth, microwave communication links are limited by the visual horizon to about 30–40 miles (48–64km). Microwaves are absorbed by moisture in the atmosphere, and the attenuation increases with frequency, becoming a significant factor (rain fade) at the high end of the band. Beginning at about 40GHz, atmospheric gases also begin to absorb microwaves, so above this frequency microwave transmission is limited to a few kilometers. A spectral band structure causes absorption peaks at specific frequencies (see graph at right). Above 100GHz, the absorption of electromagnetic radiation by Earth's atmosphere is so great that it is in effect opaque, until the atmosphere becomes transparent again in the so-called infrared and optical window frequency ranges.下面描述错误的是：