How to isolate 2 coil wireless transmitter?

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1

Hi guys,

I have two 5V wireless charger (two transmitter) and would like to have 2 charging station.
So the 2 coils will be placed horizontally and at z=0 but close about 10mm.
coil

I’m worrying about interference between the two transmitters.
So thinking to build a magnetic shield around (bottom and sides) to isolate them and concentrate the energy to the top side only. Event this charger have only 20mm max of charging distance, I like to be sure the magnetic field won’t affect any the performance of each other and do not disturb any other equipment that may be close.

How would I do that what kind of material? I hear about copper or aluminum…

Thanks

2

First I would build and try the system to see if there is actually a problem.
The spacing between the phone and the transmitter coil is pretty small so the field may not extend much past the perimeter of the coil.

Although it’s called magnetic shielding it may be useful to note that in principle you cannot shield magnetic fields, only redirect them.

The effectiveness of a material in “shielding” depends on the magnetic properties of the material and the frequency of the source.

Here is some MuMetal film that may work.
https://amzn.to/3Zq8KkP

You could just make a set of rings, glue the MuMetal film on the perimeter and see how that works.

Some similar systems. Don’t know if they work?
shorturl.at/fyzBE

There are some multidevice charging stations that use multiple coils stacked in an overlapping configuration.

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3

Thanks donkjr I will then do some experiences to see.