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Electromagnetic E/H Ratio

November 26th Fact-of-the-Day

Radio frequency energy in the space near a primarily magnetic field radiator, such as a loop antenna that is small compared to a wavelength, is primarily contained in a magnetic field. Radio frequency energy in the space near a primarily electric field radiator, such as whip antenna that is short compared to a wavelength, is primarily contained in an electric field. Even so, at a distance of several wavelengths or more from any type of electromagnetic radiator the ratio of electric to magnetic field strength (E/H) always becomes equal to approximately 377 ohms, which is the approximate electromagnetic impedance of space. ©2004 Martek International All rights reserved.


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