Help required for EMI shielding

Discussion in 'The Projects Forum' started by qingwei, Jul 29, 2013.

  1. qingwei

    Thread Starter New Member

    Jul 29, 2013
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    Hi all ,
    I am currently doing a project to shield the CPU (Equipment Under Test) from the Electromagnetic Interference susceptibility. My test requirement is based on the MIl-Std-461F radiated susceptibility 103(RE103).

    My supervisor recommend us to take the copper pipe to shield the cable . But I was unable to find the specifications of it in which why it is better than the other material.:confused:

    Do you guys have any other recommended material to shield the cable?

    I appreciate your help.

    Thanks,
    Qingwei
     
    Last edited: Jul 29, 2013
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
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    For severe condition application, marine or shipboard etc, or military use in general, you could look at mineral insulated with copper jacket, namely Pyrotanex, been used for many decades successfully.
    A lot depends on gauge and number of conductors etc.
    A cheaper alternative is metallic conduit including liquid seal metallic flexible conduit.
    Max.
     
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  3. qingwei

    Thread Starter New Member

    Jul 29, 2013
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    Thanks max for your advice:).
    Sorry for not stating clearly on the previous post on the specification of the project. My team focus mainly on land.

    Yes, thanks for the alternative advice. It is indeed a great help for my project. The liquid seal metallic flexible conduit is suitable for my project.

    Thanks a million
    --QingWei--
     
    Last edited: Jul 30, 2013
  4. MaxHeadRoom

    Expert

    Jul 18, 2013
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    BTW, if you require to terminate the L.S. Flex with MS military style multi-pin connectors, there are Conduit thread to MS thread adapters.
    Available in N.A. from Thomas & Betts.
    Max.
     
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  5. bountyhunter

    Well-Known Member

    Sep 7, 2009
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    There are two types of EMI: one is electrostatic and the other is magnetic flux. What you need to shield it with depends on which type of field is there. Copper has decent shielding properties for both types.

    There are tables for properties of flux shielding. It is directly proportional to material thickness also material type: steel is pretty good, copper is decent, aluminum is lousy. There is a material called mu metal which is super shielding material.

    http://en.wikipedia.org/wiki/Mu-metal

    http://www.asminternational.org/content/ASM/StoreFiles/06333G_Frontmatter.pdf
     
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  6. qingwei

    Thread Starter New Member

    Jul 29, 2013
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    Hi max ,
    Thank you for another of your good advice. Indeed , I would require the military style multi-pin connector. I had directed it to my supervisor to see if he wants to accept it because , he might have some other plans for it. Well , I would have to wait for his reply. In the meantime , still I would like to thank you for your advices.
    -QingWei-

    Hi bountyhunter,
    I'm still a newbie in these , so please correct me if any of the below I said is wrong.
    I understand that almost all metallic material could been a good conductor to provide a shielding to prevent EMI because the E-field will 'go' by the way of the least impedance.
    I also did some reading up on cathode and anode of the properties of the material would affect the rate of corrosion.So , I've been trying to get a list of material with their properties mainly focus on rate of corrosive , conductivity in various temperature, skin depth and permeability as I would most probably be required to do some calculations based on that.

    The link that you recommended me do provide all the data and I am glad that it is in great help to me. However , the 'asm' link only include the content page and I really look forward to see the content of the book. I searched through the library and it does not have the book. I found another book namely" The magnetic and electron structures of transition metals and alloys / edited by V.G. Veselago and L.I. Vinokurova ; translated by Paul Makenin and Kevin S. Hendzel." I am not sure it will help, I would require your recommendation. :)
    Thanks for your advices for a newbie.
    --QingWei--
     
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