1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Tapping radiowaves for energy?

  1. Mar 11, 2010 #1
    "Tapping" radiowaves for energy?

    One thing I have been thinking about lately is if it is possible to "tap" the electromagnetic waves surrounding us for energy in the same way it is possible to tap the waves of an ocean for their energy.

    I'm speaking of both natural electromagnetic waves but especially artificial waves caused by, for example radio transmitters; mobile phone base stations, wlan access points, FM/AM radio transmitters, etc.

    Is it possible to take advantage of these "wireless" power suppy units somehow? For example to drive very low energy consuming electronical devices?

    Best regards,

  2. jcsd
  3. Mar 11, 2010 #2
    Re: "Tapping" radiowaves for energy?

    Fifty years ago, it was fun to build a crystal radio, then build another wideband radio (which would not separate the stations from each other), and use that energy to power an audio amplifier to make it easier to hear the crystal radio. So, yes, it is possible, but the energy was not worth the effort other than as a demonstration.

  4. Mar 11, 2010 #3


    User Avatar
    Gold Member

    Re: "Tapping" radiowaves for energy?

    Actually, if memory serves, Nokia is attempting to do just this as a form of passive regeneration of power for their cell phones. A quick google search should find what I'm talking about.
  5. Mar 11, 2010 #4
    Re: "Tapping" radiowaves for energy?

    likely not the way you mean...a radio (receiver), a TV (receiver), and a fiber optic cable for example, require amplification using local power at the receiver to boost the very weak signal received over the air to a usable level....

    But you can tap the electromagnetic energy from lightning (perhaps),but it moves around too much I think, and of course sunlight via photoelectric cells and solar heat collectors of various types....
  6. Mar 12, 2010 #5
    Re: "Tapping" radiowaves for energy?

    I understand that the signals are very weak, but I was hoping that the multitude of sources around us - atleast in a metropolitan area - would compensate for this. Also, incorporating antennas "tuned" for the most usual or most powerful sources rather than a wideband solution could help?

    Also, I was perhaps thinking a bit into the future with nano technology devices, which hopefully will consume very little power. On the other hand, if they do consume very little power, maybe it's easier to incorporate a very small battery into the device? But then maybe this battery could be constantly charged by the very weak signals.

    My reasoning then becomes; if a device consumes very little power, the weak signals could actually contribute significantly :)
  7. Mar 12, 2010 #6
    Re: "Tapping" radiowaves for energy?

    Interesting and yes, Google served up the following result


    but it turns out they use piezoelectric technology to get energy from the motion of the mobile phone's owner.
  8. Mar 12, 2010 #7


    User Avatar
    Gold Member

    Re: "Tapping" radiowaves for energy?

    No that's not in, although good find. They announced research into it earlier last year. It may not have been Nokia either. One of the major cell phone manufacturers is going to try to passively recharge using the typical amount of radiation you have in a major city just flying around.
  9. Mar 12, 2010 #8
    Re: "Tapping" radiowaves for energy?

    I did some more googling and it turned out there already was a thread about this here on this forum, and yes, it was Nokia:

Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Tapping radiowaves for energy?
  1. Radiowaves and Heat (Replies: 6)

  2. Radiowave mediums (Replies: 6)