Calculate current on a triangle from edge currents

ju1995
ju1995 Altair Community Member
edited September 2022 in Community Q&A

Good Morning,

I export the MoM matrix (impedance matrix) of FEKO and carry out a so called Characteristic Mode Analysis, which yields surface current modes. Since the impedance matrix is defined based on the number of edges of the mesh, the surface currents are also calculated at the edges. Now I'd like to plot these surface currents in Matlab, which is only possible when having one surface current value for each mesh triangle instead of three edge currents. How exactly can I get one value for the whole triangle out of the three edge currents? I heard it involves RWG basis functions, but I'm not sure about the details...

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Answers

  • Johan_Huysamen
    Johan_Huysamen
    Altair Employee
    edited September 2022

    Dear ju1995

    The "edge currents" you mention are based on the RWG basis functions. These basis functions have a defined shape across the edge and across the surface of the triangle (towards the vertex opposite the edge). These were originally suggested by Rao, Wilton and Glisson in the following paper:

    S. M. Rao, D. R. Wilton, and A. W. Glisson, “Electromagnetic Scattering by Surfaces of Arbitrary Shape”,
    IEEE Transactions on Antennas and Propagation, Vol. 30, pp. 409- 418, 1982.

    As current on each triangle would then be the combination of the three basis functions across the three edges, the current on each triangle does not have a single value. You would have to apply some form of super-positioning of the basic function and averaging of the resulting current distribution to define a single current value.

    Kind regards,

    Johan H

     

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