Can an Electromagnetic Wave Charge a Battery?

[nickerst]

This is a theoretical question not a homework question, so if this is the wrong section to post this in please let me know. But my friend has this idea that if he sent an electromagnetic wave at a certain frequency at a surface it could create a current and this in turn could charge a battery. Does this sound at all possible to anyone? In my opinion the EM wave would jiggle the electrons back and forth but there would be no net current on the surface so it couldn't actually have a surface current. Any ideas are encouraged. Thanks!

 

[berkeman]

This is a theoretical question not a homework question, so if this is the wrong section to post this in please let me know. But my friend has this idea that if he sent an electromagnetic wave at a certain frequency at a surface it could create a current and this in turn could charge a battery. Does this sound at all possible to anyone? In my opinion the EM wave would jiggle the electrons back and forth but there would be no net current on the surface so it couldn't actually have a surface current. Any ideas are encouraged. Thanks!

Your thinking is correct. To use the AC pickup current of an antenna, you would need to rectify it to get useful DC current for charging a battery or whatever:

http://en.wikipedia.org/wiki/Rectenna

.