Electromagnetic radiations

  • #1
Confused mind
I have encountered a problem that how electric and magnetic fields at perpendicular to each other are produce in electromagnetic radiations?
 

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  • #3
sophiecentaur
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I have encountered a problem that how electric and magnetic fields at perpendicular to each other are produce in electromagnetic radiations?
This is only the case in the 'far field' of a radiator. Right up close, the fields can have a range of relative angles around, say, a simple antenna. It is only when the fields have settled down at a distance and there is only energy being transferred and not stored (as in a Capacitor or Inductor). A plane EM wave in space is the simplest case.
 
  • #4
Drakkith
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This is only the case in the 'far field' of a radiator. Right up close, the fields can have a range of relative angles around, say, a simple antenna.
Is that so? Huh. I never knew that. I thought the angle was always 90 degrees.
 
  • #5
sophiecentaur
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Is that so? Huh. I never knew that. I thought the angle was always 90 degrees.
It is when the only wave is a progressive wave. In the standing wave region the fields will be the resultant of various travelling waves in different directions. Also, in waveguides, not all the modes are TEM, there are TE modes too. Coax is always TEM, though.
Near to an antenna you can get different modes which are not TEM and it happens, I think, when you have waves from different parts of the antenna, travelling in different directions.
 
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