In dealing with a Radiation Source --be it an Antenna or a Circuit Board: -
The dominant energy in the Far Field is Electric.
-- Plane Wave radiation is how radio works 377 ohms is the impedance of free space -
The dominant energy in the Near Field is Magnetic. -
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In any high frequency signal the dominant radiation component under ~1/6 wavelength from the source, is Electromagnetic; this is referred to as Near Field radiation.
Any signal beyond ~1/6 wavelength, is Electrostatic, and is referred to as Far Field radiation; sometimes called the Plane Wave. Plane Wave radiation is how radio works and that the 377 ohms is the impedance of free space.
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发表于 2010-12-9 18:02:01
发表于 2010-12-10 09:02:21
The dominant energy in the Far Field is Electric.
The dominant energy in the Near Field is Magnetic. 
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