Subject: How do receiving antennas work

I have been confused on this subject for a long time now. I'd like to know 
what happens in the antenna once it picks up the desired radiowave. I read 
in a book that it converts it into voltage and current. But they keep 
referring to this current and voltage as a signal. It seems as if this 
signal is physically different from the current that we see in DC or AC. 

Also, I'd like to know how much current and voltage is generated in the 
antenna. Thank you for your help. I hope that someone can be able to help 
me with my confusion.

Re: How do receiving antennas work