Electronics > Beginners

How does an antenna work?

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Wartex:
I always wondered, what is the fundamental principle of operation? I get the whole "AC causes electron movement which causes RF radiation", the problem is, every forum I've been to, the last, and always unanswered question is "How do you get current flowing" if antenna is *not in a circuit*, at least galvanically?

Mechatrommer:
you need a physicist forum for this. i dont have an exact answer, just an imagination :P that electron movement is like ripple of water. in the antenna, its like a dead end tunnel where the ripple try to go out but then got reflected back. there will be no net electron movement, but this jiggling like motion, with proper tunnel/antenna length will create resonance and amplify the rippling hence electromagnetic force/wave. i imagine potential also is like pressure thats try to push and pull electrons in the antenna. maybe thats just my science fiction imagination.

Tony R:
I'm not an expert in this area but I wish to point out that if you increase the voltage on an antenna, you add charge to it, the charge will want to even out thus they are moving, a moving charge is a current.

I do know that radio waves are due to accelerating electrons. acceleration means motion so they have to be moving, and the above answer is the only way i know of that you can get movement of electrons.

Trigger:
Too much to type so...

http://youtu.be/7Sgtq-ncZAE

johnmx:
What do you mean with: “antenna is *not in a circuit*, at least galvanically”? Between transmitter and receiver?

If you understand what causes RF radiation than you know the answer of your question.

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