Scavenging Energy from Radio Waves: A Study at A Level | Sources & Results

[technophile]

I am working on an independent project at A level and have chosen to look at scavanging energy from radio waves.

i have built a rectifier circuit and tested various types of dipole to induce a dc current.

so far so good, got some very good results. however, there is very little theory/texts that pertain to this particular method or even the general idea of capturing energy from radio frequencys.

can anyone suggest some sources?

 

[Drakkith]

Would the standard theories and explanations of typical radio antennas work? I know they absorb RF energy and convert it into an electrical signal. Sounds like you would use that.

 

[technophile]

that's not a bad start but i also need something to explain how the current is made when the signal comes in from all 360 degrees; my lecturers were expecting the signals to interfere with each other and cancel out the current but it doesnt.

also, interestingly, one of the dipoles i tested was a lead sheet; my theory was that a denser material may capture higher frequency waves and thus higher energy could be produced. however, lead actually produced consistetly LESS energy. my best guess is either a) eddy currents were more prevalent in a denser material and/or b) it was so dense that movement of free electrpons was hindered.

anyone care to chip in any other ideas?

 

[saltyjordan]

http://www.youtube.com/watch?v=HnS4uwFALHE&feature=player_profilepage

check that out, i think its on the same level..? Am i right?

 

[technophile]

thats the same thing, yes - though i haven't a clue as to how he has managed to get a full volt! my experiments show the results to be on the scale of mili volts!

 

[technophile]

and that was with 100m of wire as a dipole!

 

[Drakkith]

Radio waves don't carry much energy anyways. If you have a goal of producing power, I suggest that you find another goal. Not just for that reason, but also because interferring with radio stations and communications is going to get you in trouble real quick.

However, if you are simply trying to find a way to transmit power wirelessly, then by all means go ahead. Have you though about using something like microwaves instead?