CMA of Twisted pair

Zakaria
Zakaria Altair Community Member
edited November 2020 in Community Q&A

Hi all

I am trying to simulate an unterminated twisted pair using CMA.  every time it shows me an error. 'Characteristic mode analysis cannot be used when the number of MoM basis functions is zero'.This is also the same case when I terminated the cable with resistance. If I use the MOM in the harness properties it gives me another error 'The combined MoM/MTL solution method may only be applied to shielded or single conductor cables'. Is there a way to apply the CMA analysis on the unshielded (terminated/unterminated) twisted pair?

Thanks

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Answers

  • JIF
    JIF
    Altair Employee
    edited June 2018

    Hello,

     

    I would suggest that you not try to use cable analysis if you are interested in CMA. As the message indicated, CMA is only supported for MoM and the MoM/MTL is a very special hybridisation that is only applicable for shielded cables. I also don't think you are going to get out of the simulation what you want if you try to use cable analysis.

     

    I would simply model the actual twised pair using segments (as a start or even cylinders - only for very short cables and high frequencies).

     

    Out of interest, what are you trying to investigate with CMA and twisted pair cables?

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