RF power

[Minjin]

I was reading a thread on another board earlier today where the poster was talking about just how much RF radiation there is permeating the air nowadays. Cell phones, wireless networks, and all sorts of remote controls are very widespread. The poster was mainly making a point for how this might be dangerous or otherwise bad. However, a thought jumped into my head that was completely different...

If there is so much RF radiation surrounding us everywhere and at all times, how practical would an RF "Solar cell" be? It would be a super sensitive antenna with some circuitry that would convert RF waves back to electricity. Is this at all possible? I'm guessing that it is, just not practical.

Comments?

Mark

 

[Woodchuck2000]

In order to induce a current, I'm pretty sure that the inductor would need to be moving such that it cuts field lines.
Aside from that, the problem is that there isn't one single band which has significant power - any inductor is only responsive over a fairly small range of frequencies so you'd need a massive array in order to take advantage of all the frequencies broadcast.

 

[Geniere]

As these are oscillating fields, a moving inductor is not necessary. The signal strength that would be received would be very low, in the micro-watt range in most areas. I suppose you could have a receiver within a few hundred meters of a powerful radio station (WABC in NYC) and with a very large antenna array, steal several hundred watts. Several thousand broad band receivers may provide enough to trickle charge a battery in typical locations. The Sun provides about 0.5 watts/cm*2 on the equator at hi noon, for comparison.

Regards