Jump to content

mel

Moderators
  • Content Count

    417
  • Joined

  • Last visited

  • Days Won

    25

Reputation Activity

  1. Hamsalekha liked a post in a topic by mel in How to check volume and surface area of the geometry in CADFEKO   
    This is not possible in CADFEKO, however the surface area will be given in the *.out file near the beginning of the *.out file.
    "Surface of all triangles in m*m:"
    This will obviously be the surface area of the mesh, so be careful if you have curved surfaces meshed very coarsely.
     
    You don't have to run the solver fully to get this output. You can use the check-only mode for the solver.

  2. Hamsalekha liked a post in a topic by mel in FEM incident field   
    Yes. The incident field, which is seen as part of the MoM, acts as the excitation for the FEM region.
     
     
     
  3. pmcardle liked a post in a topic by mel in FEM incident field   
    Yes. The incident field, which is seen as part of the MoM, acts as the excitation for the FEM region.
     
     
     
  4. pmcardle liked a post in a topic by mel in Multiple Frequencies at once   
    The MoM solves a single frequency at a time. For instance you cannot have two antennas, one operating at f1 and the other at f2 at the same time.
    Actually all of the solvers work this way.
     
    But if you want to solve a frequency loop and want to solve more than 1 frequency at the same time, this could be done by setting up a grid search with the optimizer and farming out the frequencies, e.g. solving then one frequency per core. Still the results would be combined as if a single frequency at a time was solved.
     
     
  5. SHAIKSHA liked a post in a topic by mel in ERROR 40631: Intersecting elements in cad feko   
    This usually happens if there are more than 1 part in the model and you did not Union all the parts that have ohmic connections.
    Or it could happen when you import a mesh and the mesh connectivity is poor.
     
    Open the OUT file in POSTFEKO. It will show the element numbers causing the error. On the Mesh tab you can find the elements in the 3D view.
    Then you will have to fix the mesh in those areas in CADFEKO, or in the external application if you imported the mesh from elsewhere.
  6. ዘካርያስ liked a post in a topic by mel in TEM Horn Antenna   
    Yes, two wires joined or a Polyline will do the job.
  7. ዘካርያስ liked a post in a topic by mel in TEM Horn Antenna   
    The wire can't be on the surface of the dielectric. Either inside our outside.
    E.g. 

  8. ዘካርያስ liked a post in a topic by mel in TEM Horn Antenna   
    I made lofts between the two PEC surfaces. This then creates a solid which has a region that you can set to dielectric,
    Then change the face properties to either PEC or dielectric.
  9. ዘካርያስ liked a post in a topic by mel in TEM Horn Antenna   
    1. The example guide examples D4 (Radhaz example) and F2 (MRI) shows how to create near field requests. 
    For far fields, several examples show creation of far field requests. Just search for "far field". 
    In terms of the number of points/increments, if unsure, you can always request continuous far fields. Example H3 (reflector antenna) shows how to do this.
    2. The wire radius should be according to the physical size that would be used, e.g. SMA has a radius of 0.65 mm.
    3. Search the Examples Guide for "continuous frequency range" or "linearly spaced discrete points", there are frequency list and logarithmic options too.
    4. The student edition limits are provided here. https://altairuniversity.com/feko-and-winprop-student-edition-limitations/
    If you need higher limits, contact your study leader for access to the full Feko license.
    5. Please clarify what you mean by delayed?
    6. Please clarify, maybe give a drawing of what you are planning to do.
    7. Yes, see Examples Guide G1 Time Domain.
  10. ዘካርያስ liked a post in a topic by mel in TEM Horn Antenna   
    Create line yes.
  11. 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.
     
  12. 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.
  13. Elektrolysator liked a post in a topic by mel in Loads in Network Schematic   
    In the below image, I modified the Example Guide model D-02 to remove the monopole and added a Voltage source in the cable schematic to the MTL cable.
    Seems simple, or did I misunderstood your question perhaps?

  14. Elektrolysator liked a post in a topic by mel in Loads in Network Schematic   
    For non-radiating network sources, the source is applied outside of the schematic by choosing the network port in the voltage source dropdown box.
    For example, in Example Guide example E-3:

  15. ዘካርያስ liked a post in a topic by mel in TEM Horn Antenna   
    You can user a wire port, yes.
    Click on the Line primitive, and use CTRL+SHIFT to snap to the edge centers of the top and bottom edges of your first image above to connect the line. 
    You must then Union the line with the horn.
  16. ዘካርያስ liked a post in a topic by mel in TEM Horn Antenna   
    Try lofting the analytical curves of the two outside edges as seen in the images below.

    For example:

     
    The position of the curves you can control with the workplane tab.

  17. SanderBash liked a post in a topic by mel in Can't mesh a face (error 18167)   
    The PEC parts you can just delete the faces not directly touching the dielectric, the "top" faces if you may.
    The dielectric, yes, should remain an enclosed volume ("Region" in details tree).
    If you look at the patch antenna or microstrip examples in the Examples Guide you will see the PEC faces are infinitely thin, touching the dielectric, but the dielectric is an enclosed volume.
  18. SanderBash liked a post in a topic by mel in Can't mesh a face (error 18167)   
    Here as an example, I have removed some, not all, of the "redundant" metallic faces. I refer to them as "redundant" since the electrical thickness at 500 MHz is very very small. It may be that in the spiral the finite thickness does play a role due to the small spacing between the "rings". So it's best to test these assumptions with sub-parts of the model that can be solved faster.

  19. SanderBash liked a post in a topic by mel in Can't mesh a face (error 18167)   
    A workaround is to split the model once into two halves.
    Then Union the two split parts.
    Mesh.
    Model cfx attached.

    Planar_spiral_2D_test_meshed.cfx
  20. ዘካርያስ liked a post in a topic by mel in Antenna   
    Yes, Feko can certainly model that.
  21. oussama1 liked a post in a topic by mel in the wire is not electrically connected to a metalic face   
    It's difficult to judge just from an image,
    If the 3 wires running into the Y direction are made from lines (which will mesh into wire segments) then their "surfaces" (defined by their radii) are purely analytical. You cannot connect to them. 
    If you draw a line going into a cylinder and Union, then there would be a connection to the cylinder surface plus a small remaining section of the line would remain on the inside of the cylinder.
     
  22. Hamsalekha liked a post in a topic by mel in Unable to do tetrahedral mesh for combined sphere   
    Sphere1 and Sphere2 touch but the mesher does not "know" this. The two spheres should be in a Union before meshing.
    The GetStarted guide and the Example guide in the help folder of your Feko installation have many examples on basic geometry construction and the Union operation.
     
  23. 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)
  24. oussama1 liked a post in a topic by mel in my simulation is slow   
    If you request S-parameters, Feko will automatically load each port with 50 Ohm (or a different value if the user specifies it).
    You have added 50 Ohm loads manually - effectively you are calculating S-parameters in a 100 Ohm system.
  25. oussama1 liked a post in a topic by mel in my simulation is slow   
    Please share some details about what you are trying to solve.
×
×
  • Create New...