magnetic shielding of electric components while allowing signal

[tianshiz]

So basically i have this powerful electromagnet that generates an electromagnetic field that can levitate another magnet and withhold a load of 12oz and still levitate:

My problem is, I want to be able to use electronics and send wireless signals through this strong magnetic field. I can shield the electronics with a thin metal sheet but my wireless transmitter cannot have this protection, since it would essentially prevent radio transmission. Additionally, even if the transmitter can be allowed to transmit, the magnetic field would have some major interference on the data transmission(right?). So I was wondering if you guys know of any special way to shield the transmitter so that
1) the electronics shielded within this magnetic field wont fry
2) the signal gets transmitted

Is a faraday's shield even going to be effective in this situation? Should I consider Mu-metal instead? Or do a combination?

 

[VEBill]

Most electronic devices are not affected by magnetic fields. There are exceptions.

Wireless signals will pass right through.

 

[electricpete]

Probably there is less concern if the magnetic field is constant than if it is varying.

=====================================
(2B)+(2B)' ?

 

[VEBill]

Good point e.p.

I was assuming it was a slowly varying field. If it's a PWM at high frequencies, then it could cause all sorts of problems.

 

[tianshiz]

thanks for the help guys. I'm not really sure if the magnetic field would be constant or varying. But wouldn't it need to vary so that the globe can be balanced? I'll contact the manufacturers for more info.

Supposing that it is pwm though, what would the solution be?

 

[MacGyverS2000]

You're asking us to solve a problem that you cannot properly define. You tell us if the field is varying, by how much, and how fast. Anything less is us shooting in the wind...

Dan - Owner

http://www.Hi-TecDesigns.com

 

[biff44]

I have done some work with wireless transmission from spinning machine tools in magnetically noisy environments, and mostly it is not a problem.

Obviously you want to have a lot of power supply decoupling at the wireless modules because that (assumed) 60 hz noise will possibly cause some demodulation/modulation problems. So big caps! Also, try to avoid long power supply leads, and battery operation would be much better.

Really the only thing about a wireless module that can not be inside of a metal farraday cage is the antenna. And the antenna can be coupled to the modules thru a very small capacitor (perhaps 100 pf) that will not pass the 60 Hz. I would make a mu-metal box to completely enclose the wireless module. I would have the antenna go thru the wall of the box with an SMA connector. I would have a series 100 pf cap between the sma center contact and the wireless module. I would use honkin big emi filtercons to get dc power thru the wall. I would use smaller filtercons (maybe 1000 pf shunt) to get the data in/out.

So, try unshielded first. If a problem, use the shield box.

http://www.MaguffinMicrowave.com

Maguffin Microwave wireless design consulting

 

[tianshiz]

thanks for the help biff44, although the manufacturers claimed its constant magnetic field, theres always a chance it might fluctuate. I'll take your tips to heart. Glad to see that it is possible to shield electric components while in a magnetic field.

 

[MiketheEngineer]

How about IR or just try it and let us know!!

 

[biff44]

Now I am confused. If you have a constant DC magnetic field, why do you care about shielding RF wireless modules at all?

http://www.MaguffinMicrowave.com

Maguffin Microwave wireless design consulting