Hello,
There may be a bug in how the currents are stored (or ordered) in the .out files. Using the Surface Current and Charges dataset object within the LUA environment, we wrote the results into a text file (please see the script below for details). We tested this with purely dielectric (epsilon_r = 2.56) and purely metallic sphere models (radius = 0.5m). Here, the spheres are illuminated by a plane wave and solved at 380MHz. As you can see from the figure below (FEKO plots on the left and the MATLAB via textfile export on the right) the current magnitudes are slightly off from FEKO, but the current distributions are correct.
We repeated this with a coated sphere model (radius = 0.5m), where the interior is a metal sphere (radius = 0.25m) enveloped by a dielectric sphere (epsilon_r = 2.56). Here, it is illuminated by a plane wave solved at 250MHz. Unlike the other cases, we noticed that even though the electric currents along the interior sphere are identical to FEKO, the electric and magnetic currents on the dielectric region are completely wrong. As shown in the figure below, the electric currents along the metallic region are as expected from FEKO, but the electric currents along the dielectric (although nearly the expected magnitude) are completely wrong. We cross-validated our textfile with the outputs from the CADFEKO .out and POSTFEKO .os / .ol files and they are the same.
I suspect there may be an ordering (i.e., indexing) problem, for example, the current values are stored at the wrong triangle index. Regarding the difference in magnitude for the purely conductive and dielectric sphere cases, this doesn't occur if you output the currents via the LUA DataSet: ExportMatFile() function, which unfortunately doesn't work for composite designs in FEKO 2020.0. Perhaps this is a consequence of the same bug?
The LUA code:
app = pf.GetApplication() app:NewProject() app:OpenFile([[path_here\coated_sphere.fek]]) -- Set up the file details absPath = [[path_here\]] -- HIGHLY recommended to hard code the absolute path! meshfile = "coated_sphere_sol.txt" -- Find all possible data files names = pf.SurfaceCurrentsAndCharges.GetNames() --Get characteristic mode model currents currents = pf.SurfaceCurrentsAndCharges.GetDataSet(names[1]) --Load a given model sConf = app.Models["coated_sphere"].Configurations[1] --Import the mesh mesh = sConf.Mesh count = mesh.TriangleFaces.Count --Number of Triangles --Get mesh values points = mesh.Points --I/O for mesh write upper-- Open a file to write to. file = io.open(absPath..meshfile, "w") --Create Column Headers Vertice Index - Position(X,Y,Z) colHeader = string.format("%s %s %s %s %s %s %s %s %s %s %s %s %s %s %s %s %s\n", "Frequency", "Element","X", "Y", "Z", "real_Jx", "realJy", "real_Jz", "imag_Jx", "imag_Jy", "imag_Jz", "real_Mx", "real_My", "real_Mz", "imag_Mx", "imag_My", "imag_Mz") --Write Column header to file file:write(colHeader) -- Get vector of all solved frequencies frequencies = currents.Axes[1] for c = 1, #frequencies do str = "" elementNum = 1 pointCount = 1 for i = 1, count do --Load mesh triangle triangle = mesh.TriangleFaces[i].Triangles count2 = triangle.Count --Number of triangle vertices for j = 1, count2 do info = triangle[j].VertexIndices -- Pre-Allocate Center of Triangle Value for ouput -- Electric Current real_Js_x = 0 real_Js_y = 0 real_Js_z = 0 imag_Js_x = 0 imag_Js_y = 0 imag_Js_z = 0 -- Magnetic Current real_Ms_x = 0 real_Ms_y = 0 real_Ms_z = 0 imag_Ms_x = 0 imag_Ms_y = 0 imag_Ms_z = 0 -- Element Centroid centroidx = 0 centroidy = 0 centroidz = 0 for ii = 1, #info do -- Get vertice location position = points[triangle[j].VertexIndices[ii]] -- Add to centroid centroidx = centroidx + position[1] centroidy = centroidy + position[2] centroidz = centroidz + position[3] -- Add Electric Currents real_Js_x = currents[c][pointCount].ElectricX:real() real_Js_y = currents[c][pointCount].ElectricY:real() real_Js_z = currents[c][pointCount].ElectricZ:real() -- Imag component imag_Js_x = currents[c][pointCount].ElectricX:imag() imag_Js_y = currents[c][pointCount].ElectricY:imag() imag_Js_z = currents[c][pointCount].ElectricZ:imag() if currents[c][pointCount].MagneticX ~= nil then -- Add Magnetic Currents real_Ms_x = currents[c][pointCount].MagneticX:real() real_Ms_y = currents[c][pointCount].MagneticY:real() real_Ms_z = currents[c][pointCount].MagneticZ:real() -- Imag Component imag_Ms_x = currents[c][pointCount].MagneticX:imag() imag_Ms_y = currents[c][pointCount].MagneticY:imag() imag_Ms_z = currents[c][pointCount].MagneticZ:imag() end -- Move to next vertice pointCount = pointCount+1 end -- Format average values as string str = string.format("%15G %15G %15G %15G %15G %15G %15G %15G %15G %15G %15G %15G %15G %15G %15G %15G %15G\n", currents.Axes[1][c], elementNum, centroidx/3, centroidy/3, centroidz/3, real_Js_x/3, real_Js_y/3, real_Js_z/3, imag_Js_x/3, imag_Js_y/3, imag_Js_z/3, real_Ms_x/3, real_Ms_y/3, real_Ms_z/3, imag_Ms_x/3, imag_Ms_y/3, imag_Ms_z/3) -- Print to file file:write(str) -- Move to next triangle in solution elementNum = elementNum + 1 end end end --Close the text file file:close() --return currents
Thanks!
