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Write short notes on Electromagnetic spectrum.

Mumbai University > Electronics Engineering > Sem4 > Fundamentals of Communication Engineering

Marks: 5M

Year: May 2014

1 Answer
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  • Electromagnetic radiation comprises of oscillating electric and magnetic field components through which information transfer can occur.
  • These oscillations are sinusoidal in nature and expressed in cycles per second or hertz (Hz).
  • The range is of these oscillations is quite wide from as low as 1 Hz and can extend up to a large value.
  • The entire range of the frequencies that the electromagnetic waves can produce is known as Electromagnetic Spectrum.
  • The electromagnetic spectrum ranges from below the low frequencies which are used for radio communication to gamma radiation at the high-frequency, thereby covering wavelengths from thousands of kilometres down to a fraction of the size of an atom.
  • Most of the frequencies of Electromagnetic spectrum are used for wide range of communication systems based on different applications.
  • Electromagnetic waves are distinguished by three physical properties, which are frequency f, wavelength λ and photon energy E.
  • The below given Table1 describes the entire frequency range of electromagnetic spectrum along with its applications.
Frequency (f) EM Spectral region Application
30-300 Hz Extremely low frequency (ELF) Power line communication
0.3-3 kHz Voice frequency (VF) Speech communication
3-30 kHz Very low frequency (VLF) Submarine communication
30-300 kHz Low frequency (LF) Marine communication
0.3-3 MHz Medium frequency (MF) AM Broadcasting
3-30 MHz High frequency (HF) Landline telephony
30-300 MHz Very high frequency (VHF) TV, FM Broadcasting
0.3-3 GHz Ultra high frequency (UHF) TV, Cellular telephony
3-30 GHz Super high frequency (SHF) RADAR, Microwave oven
30-300 GHz Extremely high frequency (EHF) Satellite communication, RADAR

Table1. Electromagnetic spectrum

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