Shielding a wireless signal

Hi, I am interested in this topic mainly with regards to Bluetooth devices but I presume it is equally relevant to wireless in general.

Can I shield my radio emitting device on one side, so that it only emits in one direction? In other words, what materials could I put in front of my router/bluetooth device to attenuate the signal? Thanks, Mike

Reply to
mikekelly100
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devices

Aluminum foil does a pretty good job

Reply to
Airhead

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:

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For the true fanatics, we have frequency selective wallpaper:
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Reply to
Jeff Liebermann

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.

Reply to
mhicaoidh

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

Mike

Reply to
mikekelly100

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.

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common (cheap) black carbon conductive foam sheets that are often used for anti-static holders for intergrated circuits work well enough.
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Reply to
Jeff Liebermann

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