Shielding a wireless signal

devices

Aluminum foil does a pretty good job

It would be helpful if you would disclose what you're trying to accomplish or what problem you're trying to solve.

You should distinguish between absorption and reflection. Both will block a signal but in different ways. A piece of sheet metal, wire mesh, or aluminium foil, will prevent the signal from going through, but will also reflect the signal to who knows where. If you're trying to control the distribution of the signal, this is not a great way to do it.

Absorption converts the RF to heat. A piece of carbon doped anti-static foam works nicely. A wet towel works well at 2.4GHz because water absorbs RF. If you like spending money, Eccosorb:

Taking a moment's reflection, snipped-for-privacy@hotmail.com mused: | | I am interested in this topic mainly with regards to Bluetooth devices | but I presume it is equally relevant to wireless in general.

Is it to direct the signal, or to contain the signal? If the latter, note that Bluetooth's range is fairly limited anyway.

Thanks for the useful info. Though I'm not too sure what you mean by 'carbon doped'.

Mike

Foam loaded with carbon granules. Polystyrene carbon foam is an fair absorber of RF. That's what RF dummy loads are made from. They are essentially resistors that convert RF energy into heat. The military paints their airplanes with a form of carbon foam plus ferrite to reduce radar reflections. Ferrite doped material is better for a wider range of (lower) frequencies.