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Radiowave transmission

  1. Oct 27, 2013 #1
    Hi, I am having difficulty determining where the electric field comes from when an electromagnetic wave is emitted by an antenna. I know that the charges accelerate between an AC voltage but where does the electric part of the EM wave come from? In a normal wire there is no electric field from the charges themselves as they are cancelled by the positive charges of the atoms. The electric field in the wire comes from the source voltage (e.g. a battery). So in an antenna does the electric field come from the AC voltage source?
  2. jcsd
  3. Oct 27, 2013 #2


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    Staff: Mentor

    Yes, the voltage source puts a charge on the antenna. Note that an antenna is not a closed circuit. Charges flow out of and back into each end at the same rate as the transmitted frequency.
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