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    • Rahul Ponginan

      Please click here for a short but important announcement   03/26/17

      Dear Users Our Commercial and Academic users around the world can use these same forums here as before i.e. the Altair Support Forum , Commercial users from India with solver queries can go to the Solver Forum for India Commercial Users , Academic Users from India and AOC India Participants are requested to go to the Forum for India Academic Users and AOC India Participants , We will be tending to all queries in all the forums promptly as before, thank you for your understanding. 

JIF

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JIF last won the day on December 27 2017

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  1. Far Field Data

    The DerivedResults module in the 2018 version (soon to be released) has a DeriveSourceAnnotation module that does the same calculations as the annotations.
  2. Polyline Refinement

    Hello FEKOFan, I'm not sure I understand and without seeing results or the model, appreciating the significant difference is difficult. I assume that you suspect that the change in the mesh is responsible for the change in the results. Since you are using a polyline for the wire, take into account that every node in the polyline will result in a mesh vertex. Thus, be careful to not place the nodes too close together (this can cause problems if your segments become "fat" and the thin line approximation is violated). If you want to refine the active element, refine it. This is easily done by setting a local mesh size on the wires of the active element. I'm not sure why you want to use the polyline refinement. If you do want to use polyline refinement instead of local mesh settings, you don't need to have the same "corners" for the refinement. The poly line refinement simply defines a region (tube) where the mesh will be refined. You would pick a radius that is big enough to enclose the elements that should be refined and exclude the elements that should not. You can use the automatic mesh settings as a guide (see the manual), but assuming that you want a fine mesh, start with lambda/20. The best would be to do a mesh convergence test - refine the mesh until the results stop changing much. Note that since you are working with wires, you do have a lower limit for the mesh segment length that is determined by the radius of the segments. The segments use a thin wire formulation and thus the segment should be much longer than its diameter. I would use segments that are at least 5 times longer than its diameter, but 10 times or more would improve the approximation. This is a strange question in my opinion. You seem to feel that the automatic meshing is not good enough, but you don't know what mesh settings to use. The only answer for this is to do a mesh convergence study.
  3. Far Field Data

    Hello FEKOFan, You are indeed correct that these parameters are not currently available in numeric form. Since annotations are not automated in POSTFEKO yet, they will have to be calculated yourself. I'll add a feature request as you suggested so that this can be implemented in FEKO direction in the future. The problems that we have had with these parameters in the past is that they are easy for calculated, based on some assumptions such as the existence of a main beam and side lobes. However, this does not exist for all antennas and then these parameters can't be evaluated. It also depends on what points (of the far field) the user included in the request. If you calculate these from far field DataSets, you can get them in numerical form. You could use the DerivedResults module (see shared/lua/DeriveResults/docs/modules/DeriveFarField.html in the FEKO installation folder for some documenation) to easily calculate the gain and other parameters and from that derive the quantities that you seek. If you do write some nice scripts, share it here with the rest of the FEKO community. ;-)
  4. CADFeko - script

    Hello Sneezy, You are correct in stating that you need to make both changes at the same time and the code you have in the first section is correct. The problem you are most likely running into is that you have a PEC region and what to set the faces to metal (lossy). That setup does not make sense and CADFEKO is preventing you from doing it - it will do the same if you try to do it in the GUI, not just the API. You need to set the region to free space (hollow) or a dielectric (more likely for your substrate). The following code illustrates that it works and uses the same strategy as your first piece of code. This code runs when copying it into a new script. app = cf.GetApplication() project = app.Project -- New project project = app:NewProject() -- Added medium "Dielectric1" properties = cf.Dielectric.GetDefaultProperties() properties.Colour = "#CF474F" properties.Label = "Dielectric1" Dielectric1 = project.Media:AddDielectric(properties) -- Added medium "Metallic1" properties = cf.Metal.GetDefaultProperties() properties.Colour = "#A747BF" properties.Label = "Metallic1" Metallic1 = project.Media:AddMetal(properties) -- Created geometry: cuboid "Cuboid1" properties = cf.Cuboid.GetDefaultProperties() properties.Label = "Cuboid1" Cuboid1 = project.Geometry:AddCuboid(properties) -- Renamed "Cuboid1" to "Substrate" Cuboid1.Label = "substrate" -- Change the region from PEC. Here I change it to a dielectric (substrate), but free space would also work Region1 = Cuboid1.Regions["Region1"] properties = Region1:GetProperties() properties.Medium = project.Media:Item("Dielectric1") -- or use "project.Media:GetFreeSpace()" Region1:SetProperties(properties) -- Changed settings for geometry entities Face1 = Cuboid1.Faces["Face1"] properties = Face1:GetProperties() properties.Medium = project.Media:Item("Metallic1") properties.Thickness = "0.002" Face1:SetProperties(properties)
  5. fittedspline In Editfeko

    Hello MOHAMED HAMDALLA, As you have noted, EDITFEKO does not have a fitted spline and we don't intend to extend EDITFEKO (or rather the RPEFEKO language) to have it in the future. Your options are: Use CADFEKO (not sure why you need to use EDITFEKO, since CADFEKO also support scripting) Use CADFEKO to fit and mesh the line and import the meshed line in EDITFEKO (IN card that imports the segments from a *.cfm file) Fit the points yourself and import the fitted points into EDITFEKO
  6. which formulation is used ?

    In that case, I suggest you work with the original RWG paper (http://ieeexplore.ieee.org/document/1142818/ , S. M. Rao, D. R. Wilton, A. W. Glisson, "Electromagnetic Scattering by Surfaces of Arbitrary Shape", IEEE Transactions on Antennas and Propagation, vol. AP-30, no. 3, pp. 409-418, May 1982). That is where I started.
  7. Using symmetry for modeling simple array

    Hello Taram This s a really old version (in my opinion). The oldest I have installed on my system currently is 2017.0. Please try to upgrade. The problem in your model is your S-parameter request. The request that you have is for only one of the ports. The resulting model would excite the port, but not the other port and thus your excitation contradicts the specified symmetry. Even if you add the other port to the S-parameter request, you will run into the same problem, since it will excite one port and load all the other ports, then excite the next port. In this process, the symmetry is violated (exciting the one side of the symmetry plane, but not the other). I'm not sure why you are using symmetry on such a basic model, but maybe it is just and example. If you want the mesh to be symmetrical, then use geometrical symmetry and you won't run into the problem. If you want the active reflection coefficient, simply excite all the ports that you would like to have active an look at the reflection coefficient at the port of interest. I'm not sure what you are trying to calculate with the equation above. If you do have a model with 10 or 100 or more ports and you want to add the reflection coefficients in some way, I would use the scripting feature (I can't remember if it is available in version 7.0, but I suspect it might be).
  8. which formulation is used ?

    Hello ALM, What exactly do you want to know? The short answer is that FEKO uses RWG basis functions and uses an adaptive weighting scheme (and not full Galerkin testing). FEKO also support higher order basis functions and many other specialisations. What do you want to do with the information? If we know the goal, we might be able to give you more specific answers.
  9. How to change legend font size in PostFeko

    Hello Pearl, Yes, this is possible. The settings are available on the Preferences dialog. Take note that some settings require POSTFEKO to be closed and relaunched for the changes to become active and I think the fonts one one of those settings.
  10. How to create an irregular near field request

    Hello sangwoo.kang CADFEKO currently does not support an irregular grid (arbitrary points) near field request. It is on our feature backlog an will be available in a future release. If you want to do this in CADFEKO, you will have to create a new near field request for each point. This is not ideal, but it will get you the field values that you need. If you want to venture into EDITFEKO, the FE card does support an arbitrary points. I'll comment on this issue that you wanted to create an arbitrary point near field request in CADFEKO.
  11. .mat file in POSTFEKO

    In that case, you won't be able to import the file in POSTFEKO - that is not the *.mat file that POSTFEKO support. You need to use the mat2ascii file to convert the file to a human readable format. The .mat.0, .mat.1, etc. indicates that you are running in parallel. Could you run sequential (single core) and run the mat2ascii utility on that file and see if you then get what you are looking for?
  12. .mat file in POSTFEKO

    Hello EMCanuck1, That reference to a *.mat file is about Matlab / Octave *.mat files. It does not sound like it is the *.mat file you are referring to. I think you want the *.mat file that the FEKO solver export (MoM impedance matrix), correct? Or are you talking about something else?
  13. A bunch of little spheres filling the Sphere

    Hi Alzaabi, What part of the problem are you stuck at? I would think the problem consists of three parts: Determine the points on the sphere. This is a mathematical (packing) problem and simply searching with google for "equispaced points on sphere" should give you more than enough to get something going. I have seen articles about this, but I have never implemented any of these. Determine the number of points for your radius (big sphere and small sphere). Put it all together in a Lua script in CADFEKO to create the spheres. I could also have added another item - hope you don't run out of resources to perform the simulation. It sounds like a problem that could be quite expensive to simulate, depending on the distance between the spheres (elements should be smaller than the gap between them usually), the number of spheres and the number of elements required to accurately represent the spheres. Please post your solution on the forum when you have completed it. It sounds like something that could look interesting. I'm also interested to know what you are trying to simulate - I'm guessing RCS reduction, but for that I would probably rather use periodic boundary conditions (PBC).
  14. How can we use FEM line port

    Hi Based on your image, it looks like the source you are looking for is the "impressed current source" or a wire with a voltage source on it. As Peter said, have a look at the examples.
  15. Create automatically multiple port

    Please consider logging new problems in new threads. ;-) The problem is that you are defining a point that only take three coordinate numbers. You can either create a named point and use that named point in the translate (the named point will then use the variable) or you can set the To and From fields directly (without defining a point). Below is an example that uses the second option. my_project = cf.GetApplication():NewProject() --Create the wire startPoint=cf.Point(0,0,0) endPoint=cf.Point(0,0,0.1) my_line = my_project.Geometry:AddLine(startPoint,endPoint) --Create the ellipse ellipse = my_project.Geometry:AddEllipse(startPoint,0.1,0.1) -- Union the line and ellipse my_Union = my_project.Geometry:Union({ellipse,my_line}) --Copy and translate the union gapx = my_project.Variables:Add("gapx", 3, "space between each dipole") -- Changes w.r.t. your script here -- START properties = cf.Translate.GetDefaultProperties() inspect(properties) -- just for you to see what the properties look like properties.From.U = 0 -- This can take numbers or strings properties.From.V = "0" properties.From.N = startPoint.Z properties.To.U = 0 properties.To.V = "gapx" properties.To.N = 0 my_Union:CopyAndTranslate(properties,3)
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