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lostarmour

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  1. lostarmour liked a post in a topic by mel in Aperture FreeSpace reflection   
    Try a lossy coated surface around the outer parts of the ground plane.
    An absorber has er=ur and and electric losses=magnetic losses. 
    How wide this surface should be, how thick, and what parameters to use is up to you.


    I assume you used a mesh of lam/25 because of the waveguide port. You can use a Coarse mesh setting and just set a local finer mesh on the waveguide port face in the details tree. This will save substantial resources.
     
  2. lostarmour liked a post in a topic by mel in Aperture FreeSpace reflection   
    The waveguide source reflection coefficient will be the ratio of the incident vs reflected power. So any non-ideal flange (impedance match with free space) would deteriorate this coefficient.
    If the flange causes higher order modes to be excited, at e.g the junction, you would need to set a higher number of modes to include (capture) at the waveguide port on the advanced tab of the waveguide port dialog. This will however require a finer local mesh setting on the waveguide port face.
     
    An aperture is allowed in an infite ground plane (Sommerfeld option, see Example guide A.10.2, "aperture triangles in an infinite ground plane") but you won't be able to use a waveguide source with the infinite ground plane. This is not supported.
    You would have to continue using the finite ground plane.
  3. lostarmour liked a post in a topic by mel in How exactly near field sources radiate?   
    A detailed explanation of usage is given in the User Manual - look for the section, "AP card" (in the 2019.3 manual it is from page 937).
     
    (The AP card is another name for the aperture source, the card referring to entries in the .pre file which is written by CADFEKO automatically, or in advanced use cases, by the user)
  4. lostarmour liked a post in a topic by mel in Too many modes on the circular waveguide port   
    I would have to check with the developers on this specific error message, limitations, etc.
    This will probably only be in the 2nd week of January.
  5. lostarmour liked a post in a topic by mel in Too many modes on the circular waveguide port   
    This happens when the waveguide is over-moded. For example if a horn antenna is designed for 3 GHz and you solve it for 10 GHz there will be many propagating modes, where, usually, you would want only 1 mode to propagate.
  6. lostarmour liked a post in a topic by mel in FEM mesh size when a finite conductivity is introduced   
    Yes, see "Automatic Meshing for Regions" in the Altair_Feko_User_Guide.pdf
  7. lostarmour liked a post in a topic by mel in FEM mesh size when a finite conductivity is introduced   
    Feko will mesh the FEM tets according to the wavelength inside the medium, so definitely defining a conductivity will reduce the mesh size.
  8. lostarmour liked a post in a topic by mel in Medium of the faces in FEKO   
    >> the meaning of a face with a medium as layered dielectric as I showed in the question means that it is a thin dielectric sheet only
    Yes!
  9. MvdM liked a post in a topic by lostarmour in Cross Polarization with Monostatic RCS   
    Yes, it is very helpful. Thanks a lot. 
  10. lostarmour liked a post in a topic by MvdM in Cross Polarization with Monostatic RCS   
    Hi @lostarmour
     
    Please see this post:
     
    Does that help?
     
    Kind regards
    Madelé
  11. lostarmour liked a post in a topic by mel in Medium of a polygon in Feko   
    PEC is treated as infinite conductivity.

    The "gaps" inside the wire model is of the order of the wavelength so I would not say these models are equivalent. 
     
  12. lostarmour liked a post in a topic by mel in Explicitly define UTD and PO solvers   
    This model is not suitable for UTD.
    UTD is for electrically very very large surfaces. There are small details in the model not suitable for UTD assumptions.
    You would have to use either MoM or MLFMM. (With multiple incident angles, the MoM might actually be the fastest, if you have enough memory for an in-core solution)
    PO would be faster, but again there are small geometrical details and possible resonances there would not always be modeled by the PO.
  13. lostarmour liked a post in a topic by Torben Voigt in ERROR 33238: Not enough memory available on the hard disk for an out-of-core file   
    Hi @lostarmour,
     
    Use the attached model: 08262019_Feko_two_blades_alt_2018.cfx
    What you probably didn't do is coarsening the mesh.
  14. lostarmour liked a post in a topic by Q.Nguyen-Dai in Mesh error in STL format   
    Sorry, I don't know CADFEKO. But I can confirm you that your STL is valid & readable 
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