What's the difference between a helical antenna and a helical coil?

Discussion in 'General Electronics Chat' started by zero_coke, Oct 20, 2012.

  1. zero_coke

    Thread Starter Active Member

    Apr 22, 2009
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    I'm a bit confused and I would appreciate it if someone could explain the theory behind this: Say you have a helical antenna, one end of the antenna is connected to a coax cable and the other end is just let loose right? Where's the ground connection for this antenna?

    And my second question is, say you had the exact same helical coil antenna but you applied a + and - voltage at both ends. Is this the same thing? I mean, do these two (helical antenna & helical inductor coil) produce the same EM fields and whatnot?

    I'm asking this because I think what the guys at MIT did for wireless power transfer is they they used two coils but I'm not sure if they're antennas or simple LC circuits where those giant coils were inductors...
     
  2. bertus

    Administrator

    Apr 5, 2008
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    Last edited: Oct 21, 2012
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  3. crutschow

    Expert

    Mar 14, 2008
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    To transfer power I believe only the magnetic field was used, not the EM field.
     
  4. zero_coke

    Thread Starter Active Member

    Apr 22, 2009
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    Yes, which is what I'm wondering: Should I be using an antenna in this case or just an oscillating LC circuit? I don't understand...wouldn't it be better to use an LC circuit because it can never radiate harmful E-field since it's confined to the plates of the capacitor only?

    Why would anyone want to use the helical antenna instead of a helical coil with a capacitor?
     
  5. zero_coke

    Thread Starter Active Member

    Apr 22, 2009
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    What is the benefit of using a self-resonant coil to achieve resonance when I could simply use an LC combo to do it?
     
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