How does an antenna receive and transmit specific frequencies for RF devices?

[Miss Amy]

1. For RF devices that charge/take in energy through RF waves, does it only take in electricity from a frequency it's wired/set to pickup/receive or does it get electricity from all RF waves?
2. Can an antenna fold in (collapse but still connect like tent poles) and still remain operational like it does before?
3. Can a loop antenna receive transmissions from all directions?
4. Can loop antennas be directional while transmitting, especially when they're small?

If you can answer some, that would be great. Have a nice day!

 

[berkeman]

Is this for schoolwork? If so, please repost in the Homework Help forums using the Template there.

If not (just for your curiosity?), can you please show us what you have been reading so far? The loop antenna questions are especially easy to answer on your own, IMO...

 

[sophiecentaur]

or does it get electricity from all RF waves?

If I had £1 for every time I hear this question, I would be a wealthy man!
The term "electricity" is not appropriate here - that's a general term for the whole phenomenon. What counts is Electrical Power. An antenna is subject to the whole spectrum of EM waves that are passing by and through it but it will be 'Matched" only to a narrow band of frequencies which will allow (very low amounts of) power to flow into the down-lead and into the receiver. The receiver will have a further, narrower, band pass filter so that it only amplifies and detects frequencies in the wanted signal. Other signals are just 'ignored' due to this filtering process.