I want to use an electrostatic shield to shield a circuit from an electric field produce by a solenoid. There is component in my circuit that I want to be exposed to the magnetic field of the solenoid, and it is in the centre of the circuit.

The frequency I am driving the magnetic field at is quite high for a magnetic field, 10 - 20 MHz.

Will the electrostatic shield also shield my magnetic field? I imagine it will, but thought to ask in case my assumption is wrong. And if needed to get around this would a gap in the shield around the component work? Or would I need to be more creative?

And any suggestions of a suitable material for the shield would be appreciated also.

Thanks in advance for any help.


  • 1
    $\begingroup$ An ac magnetic field will induce eddy currents in any conducting electrostatic shield and that will attenuate the magnetic field. I had a project in which we had a 10 kHz ac-driven electromagnetic coil and wished to shield a nearby circuit from the electric field but not the magnetic field. We simply used a thin foil about 50 microns thick made of some molybdenum alloy, I believe. We searched around for thin metal foils which had a relatively high electrical resistivity. You may have to just experiment with some thin metal foils and see what works since you are working at higher frequencies. $\endgroup$ – Samuel Weir Jun 7 '18 at 19:54
  • $\begingroup$ Electric field is zero inside a conducting shell. $\endgroup$ – Anurag Jun 8 '18 at 6:44
  • $\begingroup$ Sorry I thought I had replied to the comment previously. @SamuelWeir thank you for your reply, it is a very useful bit of information for me $\endgroup$ – Dave Jun 19 '18 at 13:52

A possible way to achieve your goal is to use a soft ferrite rod or a U-shaped core to extend the magnetic field from the solenoid, through a hole in the electrostatic shield, to the component that needs to be exposed to the magnetic field. The ferrite would be acting as a light pipe, except that it will be directing magnetic field lines instead of light.

Since the high frequency magnetic field inside the ferrite will be generating high frequency electric field around it, you would have to extend the electrostatic shield as well (by adding a sleeve or making it bigger) to cover the ferrite all the way to the target component.


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