The Electromagnetic Spectrum

The electromagnetic spectrum is the entire range of electromagnetic radiation according to the wavelength or frequencies. It has a range of frequencies from 1Hz to Hz. The waves in order of increasing frequencies are radio waves, microwaves, infrared rays, visible light, UV rays, X-rays and gamma rays.Among these range, the frequencies between Hz to Hz are used for communication.

The following diagram shows the electromagnetic spectrum. The first figure gives the full range of frequency spectrum while the second figure elaborates that part of the spectrum which can be used for data communication −

The section of the spectrum in the range of radio waves and microwaves has been divided into a number of frequency bands as officially referred by ITU (International Telecommunication Union). These bands are rated from VLF (Very Low Frequency) to EHF (Extremely High Frequency).

The frequency bands and their uses in communication is tabulated as follows −