Science Buddies: "Ask an Expert"

Hi
I'm trying to work out for my experiment how to block RFID signals. I made a box that closes and used aluminium inside to try and block the signal however the signal still seems to work sometimes. I'm using a car key for the RFID signal.
Should I be using something like copper instead to block the signal from escaping the box? I just read that anodized aluminium doesn't block signals as well. I'm thinking maybe copper would block the signal better? Or would some kind of lining inside the box block the signals as I'm guessing the signal bounces around inside the box as its aluminium inside?

Any help appreciated. Thanks

Hi scienceworld99,

It sounds like you're trying to make a Faraday cage.

An initial attempt could be to add more layers of aluminum using aluminum foil or an aluminum baking tray.

Yes, copper mesh is often used for electronic shielding, so that would be worth trying!

One way you could quantify signal blockage would be to measure how far away the key's RF signals still work, with and without copper/aluminum. This would help gauge the effect of thicker aluminum layers or different materials.

I hope that helps. Please let us know if you have any more questions.

Best,
Charles