Jump to content

FieldForcer

Members
  • Content count

    51
  • Joined

  • Last visited

About FieldForcer

  • Rank
    Advanced User

Profile Information

  • Country
    India
  • Are you University user?
    Yes

Recent Profile Visitors

The recent visitors block is disabled and is not being shown to other users.

  1. FieldForcer

    Mesh doesn't show up in solution

    Hi mel, I don't have wave-guide port, and video suggests using FEM modal port. Does it mean I change voltage port to FEM modal port? Also video mentions applying FEM to dielectric regions, but that option is unavailable in Properties of brainwhitematter mesh. What am I missing? Is there a method to define better mesh, and apply FEM/MoM solver? Figures8Coil_MIDA.cfx
  2. FieldForcer

    Mesh doesn't show up in solution

    Hi Torben, With Use model mesh option, remeshed geometry has too many triangles. I agree with mel. This simulation will require enormous RAM. When i executed simulation, I received following error: I tried to find if something is wrong with geometry, and if mesh could be repaired with following options. No clashes were detected, and I still get Error 38878.
  3. FieldForcer

    Mesh doesn't show up in solution

    Hi mel, Your presumption is correct. I changed Front medium to Free Space, and turned off Low Frequency Stabilization in Solver Settings because low frequency stabilization and dielectric bodies (SEP) are not allowed in the same model. Mesh gives same warning as before meaning I dont' have control over mesh of BrainWhiteMatter. When I execute simulation, solution requires enormous memory because BrainWhiteMatter mesh is too fine. I used coarse mesh for wires, and can't play with White_Matter mesh. How to scale down memory requirement? Thanks, FieldForcer P.S.: Attached is updated cfx file. Figures8Coil_MIDA.cfx
  4. Hi, I executed a time-domain simulation on a brain skull. And I get following result. In POSTFEKO, I want to select elements that have magnetic field value above a threshold. How can elements above a threshold value be selected in POSTFEKO? How can surface area and volume of these elements be calculated in POSTFEKO? Units of Surface Current Magnitude can't be displayed in POSTFEKO. 3.How can units of surface current be displayed? FieldForcer
  5. FieldForcer

    Mesh doesn't show up in solution

    Hi, I imported a mesh from stl file in CADFEKO. When I right click on properties of this geometry, it shows that Front and Back medium are assigned White_matter property, but Face Medium is set to arbitrary Dielectric boundary. I didn't define Dielectric boundary, but I did define White_matter property. Problem is Face medium drop down list does not show White_matter, and I can't select it. As a result mesh has some arbitrary Dielectric boundary. When I mesh model, I receive a Warning 16097. Next, I executed a frequency sweep solution with following option: CEM validate didn't detect any issue. After execution, the solution obtained doesn't show any mesh. What is solution to such a problem? I have attached both cfx, pfs, and stl file. Thanks in advance, FieldForcer P.S.: Earlier Peter Futter suggested I write lua script. I don't understand workflow of writing such a file to solve mesh issue. Figures8Coil_MIDA.cfx Figures8Coil_MIDA.pfs Brain_White_Matter.stl
  6. FieldForcer

    Direction of Total gain in 3D view is disoriented

    Hi Torben, Wires thinner than 0.8mm are not used in antenna design. I can't think of a reason to used 0.25mm wire unless there is a bundle of 8 such wires. Loop implies a closed circuit. Antenna examples (ref. FEKO user manual) directly apply voltage source, without closing circuit for feed-wire. I did the same, if that is what you referring to being unrealistic. By default, PEC ground plane is created at z=0 only. I can't create a PEC plane at side of the port. This time again CEM validate didn't detect any error. But while execution, job was terminated with ERROR 39138: Invalid specification of an infinite ground plane: geometry not allowed below the plane surface I had to shift entire model above z=0 plane, and then I didn't receive any error. Addition of PEC plane didn't affect surface current, and gain increased to 10. Still origin of lobes is by default at center of coordinate system, and not center of reflector. Antenna can't gain from receiving direction. Any antenna experts to help with realistic antenna design in CADFEKO ? Thanks, FieldForcer
  7. FieldForcer

    Direction of Total gain in 3D view is disoriented

    Hi Torben, That's a good suggestion. Currently lambda ≈ 29.9mm, and segment length = lambda/12 ≈ 2.5mm. That gives wire radius of 1mm < 2.5mm. CEM Validation works for 0.7mm radius, but not for 0.8mm. What wire radius will be realistic? I do want to make it realistic. I guess you are suggesting that loop should close for current to return back. However I checked back with design given to me, and it doesn't have a path for return current. I looked at the result for wire-radius = 0.7mm, and x=0 geometric symmetry. Lobes indicate that there is minimum total gain along x-axis, and maximum total gain along z-axis. I would expect that when feed-wire is excited, electromagnetic waves travel towards reflector, and as a result, there should have been minimum gain along y-axis. I am missing out sth crucial. Why don't simulation give zero gain along y-axis? Thanks, FieldForcer
  8. FieldForcer

    Notifications not sent from forum to my email

    Forum notification is sent as an email. Ergo email settings shall not affect notification settings sent from forum. I have made the changes you suggested in notification list. Thanks Pete.
  9. FieldForcer

    Direction of Total gain in 3D view is disoriented

    Hi Torben, I enforced geometric symmetry at z=0 plane. I created a voltage source at end of vertical wire. For simulation purpose, as far as I understood, feed-wire never returns back, and loop never closes. This approach gives me a solution. And I tried to mesh model again, and received Error 16222. Clearly geometric symmetry does not give a solution regardless of location of voltage source on feed-wire. Additionally, mesh size is playing a role here. CEM validates Coarse mesh. And with Standard mesh, I get warning. What can be done? Solution obtained with those warnings has an antenna gain of 9, and surface currents are unmatched with previous results. Lobes are pointing in +z-direction, and they are symmetrisch. FieldForcer
  10. FieldForcer

    Direction of Total gain in 3D view is disoriented

    Hi Torben, I tried with suggested increments, and gain increased to 11.25 with same surface current as earlier. Interestingly far-field request spacing has no effect on surface current, and directly impacts only antenna gain. Total gain is asymmetrisch. How can it be made symmetric? Das war ein altes Design, und ich musste es bearbeiten. Ich habe eine neuere Modelldatei angehängt. My guess is feedwire itself may be making total gain asymmetrisch. FieldForcer ParabolicAntenna.cfx
  11. FieldForcer

    Direction of Total gain in 3D view is disoriented

    I redefined geometrical parameters, and got some solution. And later I requested far-field with finer spacing. Though surface currents remain same, but total gain reduces. Only difference in above two results is spacing of far-field request.
  12. FieldForcer

    Error 18071, and Simulation with Voxel Mesh Geometry

    Halò Peter, Mòran taing. I can't wait to indulge myself in lua programming. I began scripting right away. I opened Script Editor in CADFEKO, and imported MIDA_v1.txt file and received Error 17712. I have attached *.lua file. How shall I import properties specified in .txt file in CADFEKO model? I deleted all the material properties, and kept only one dielectric. Still I can't proceed with solution. CEM validation didn't detect any error. Also, in .txt file should I add material properties in 4th column before tissue names or after tissue names in 5th column? FieldForcer Untitled.lua
  13. FieldForcer

    Direction of Total gain in 3D view is disoriented

    Thanks a lot for correcting out "lambda". There is an alternate instance of wire (lower-right side of figure). Yellow instance is pointing in negative y-direction. I am unsure where that came from, but for sure is causing problem. The design conveyed to me does not have wire going through reflecting surface. Can you please upload edited model?
  14. FieldForcer

    Notifications not sent from forum to my email

    Even though notification setting is ON, I didn't receive notification of your post.
  15. Hello, I post on Altair forum for FEKO-related simulations. Earlier I used to get notifications whenever there was a reply to my post. This was an excellent feature because it helped me in organization of my work. For sometime now, even though I turn notification tab ON, I do not receive any. How can I be notified of replies? FieldForcer
×