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Appendix
Reference information is provided in the appendix.
EDITFEKO Cards
Each geometry and calculation request are entered on a separate line in the .pre and are referred to as cards.
Geometry Cards
Geometry cards are used to create geometry and are placed before the EG card in the .pre file.
IN Card
The IN card is used to include external files. These files may be other .pre files (which are included as if they were part of the master file) or mesh data files containing wire segments, triangles, quadrangles, tetrahedral volume elements and/or polygonal plates (in FEMAP neutral, ASCII format, NASTRAN, AutoCAD DXF, NEC model, CONCEPT geometry, STL, PATRAN neutral, ANSYS CDB, ABAQUS, GiD or I-DEAS UNV mesh files).
Import CONCEPT Geometry File
With this option one may import CONCEPT³⁹ geometry files

Welcome
Release Notes
See what's new in the latest release.
Get Started
The Feko Getting Started Guide contains step-by-step instructions on how to get started with Feko.
Examples
The Feko Example Guide contains a collection of examples that teaches you Feko concepts and essentials.
Introduction to Feko
Feko is a comprehensive electromagnetic solver with multiple solution methods that is used for electromagnetic field analyses involving 3D objects of arbitrary shapes.
CADFEKO
CADFEKO is used to create and mesh the geometry or model mesh, specify the solution settings and calculation requests in a graphical environment.
POSTFEKO
POSTFEKO, the Feko post processor, is used to display the model (configuration and mesh), results on graphs and 3D views.
EDITFEKO
EDITFEKO is used to construct advanced models (both the geometry and solution requirements) using a high-level scripting language which includes loops and conditional statements.
Feko Solution Methods
One of the key features in Feko is that it includes a broad set of unique and hybridised solution methods. Effective use of Feko features requires an understanding of the available methods.
Optimisation in Feko
Feko offers state-of-the-art optimisation engines based on generic algorithm (GA) and other methods, which can be used to automatically optimise the design and determine the optimum solution.
Feko Utilities
The Feko utilities consist of PREFEKO, OPTFEKO, ADAPTFEKO, the Launcher utility, Updater and the crash reporter.
Description of the Output File of Feko
Feko writes all the results to an ASCII output file .out as well as a binary output file .bof for usage by POSTFEKO. Use the .out file to obtain additional information about the solution.
Feko Application Macros
A large collection of application macros are available for CADFEKO and POSTFEKO.
Scripts and Application Programming Interface (API)
CADFEKO and POSTFEKO have a powerful, fast, lightweight scripting language integrated into the application allowing you to create models, get hold of simulation results and model configuration information as well as manipulation of data and automate repetitive tasks.
Appendix
Reference information is provided in the appendix.
- Application Programming Interface (API)
  CADFEKO and POSTFEKO have a powerful, fast, lightweight scripting language integrated into the application that allows you to create models, get hold of simulation results and model configuration information and much more.
- EDITFEKO Cards
  Each geometry and calculation request are entered on a separate line in the .pre and are referred to as cards.
  - Geometry Cards
    Geometry cards are used to create geometry and are placed before the EG card in the .pre file.
    - ** Card
      With this card a comment line can be defined whereby all text in this line is ignored.
    - BC Card
      The BC card is used to define the boundary layers for an FDTD voxel mesh.
    - BL Card
      The BL card is used to connect two points to form a line, which is then subdivided into wire segments.
    - BP Card
      A mesh of surface triangles in the shape of a flat parallelogram can be created with this card. In general, this card is replaced by the PM card. This card should only be used when the user wants to force the very regular meshing that this card produces.
    - BQ Card
      This card defines a mesh of surface triangles in the shape of a flat quadrangle.
    - BT Card
      This card defines a mesh of surface triangles in the shape of a flat triangle.
    - CB Card
      The CB card can be used to change geometry element labels that have been previously defined. Labels that are associated with points, segments, triangles, cuboids, polygonal plates and tetrahedral elements can be updated.
    - CL Card
      This card defines an arc consisting of wire segments.
    - CN Card
      This card is used to reverse the normal direction of previously created triangles or polygonal plates, for example after importing CAD data.
    - DC Card
      Domain connectivity (discontinuous Galerkin domain decomposition method) can be used to connect a discontinuous mesh and geometry where one is a static mesh (for example, a large imported car model) and the second is dynamic parameterized geometry (for example, a small antenna).
    - DD Card
      Domain decomposition can be used to store parts of a method of moments solution in a file to be reused in future simulations. The stored part must remain static but the rest of the model can change.
    - DK Card
      This card defines an eighth of a sphere, meshed into cuboidal elements, for solving with the volume equivalence principle in the MoM.
    - DP Card
      The DP card is used to define points in space. These points are used to define the extent and orientation of other geometric entities and to locate excitations.
    - DZ Card
      The DZ card is used to create a cylindrical shell, meshed into cuboidal elements for using the volume equivalence principle in the method of moments. The meshing parameters as set at the IP card are used, and the medium as set at the ME card is assigned to all created cuboidal elements.
    - EG Card
      The EG card indicates the end of the geometrical input. It is essential that the EG card is used.
    - EL Card
      A mesh of surface triangles in the shape of an ellipsoidal section is created with the EL card.
    - FA Card
      This card is used to define a finite antenna array which includes mutual coupling and edge-effects.
    - FM Card
      The FM card is used to instruct the Feko solver to calculate the solution using accelerated methods, for example, using the multilevel fast multipole method (MLFMM) or adaptive cross-approximation (ACA). An option is available to apply compression to looped plane wave sources.
    - FO Card
      The FO card is used to define an area in which the surface current density is an approximation.
    - FP Card
      Options related to the Feko solution parameters is set using the FP card. The basis functions used when using FEM or MoM is set globally or on specific labels.
    - HC Card
      The HC card creates a cylinder with a hyperbolic border.
    - HE Card
      The HE card creates a helical coil, consisting of wire segments.
    - HP Card
      The HP card creates a plate with a hyperbolic border.
    - HY Card
      With this card a hyperboloid section can be created.
    - IN Card
      The IN card is used to include external files. These files may be other .pre files (which are included as if they were part of the master file) or mesh data files containing wire segments, triangles, quadrangles, tetrahedral volume elements and/or polygonal plates (in FEMAP neutral, ASCII format, NASTRAN, AutoCAD DXF, NEC model, CONCEPT geometry, STL, PATRAN neutral, ANSYS CDB, ABAQUS, GiD or I-DEAS UNV mesh files).
      - PREFEKO File
        This option is used to include cards and commands (such as variable definitions ) from a separate file. You may, for example, create a single file with an antenna which is then imported into different environment models.
      - FEMAP Neutral File
        This option is used to import models generated by the commercial CAD meshing program FEMAP. The models must be exported from FEMAP in the FEMAP neutral file format (.neu).
      - Import Special ASCII Data File
        This option is used to import meshes stored in the geometry data file as specified below.
      - Import NASTRAN File
        With this option, PREFEKO can import a model from a NASTRAN file. It supports both 8-character and 16-character wide column based files as well as comma separated files. NASTRAN files in cylindrical, spherical coordinate systems, as well as files in Cartesian coordinate systems are supported. Only the keywords GRID, CTRIA3, CQUAD4, CTETRA, CBAR and CROD for nodes, triangles, quadrangles (divided into two triangles along the shortest diagonal), tetrahedral elements, and segments are processed.
      - Import AutoCAD DXF File
        This card allows the import of .dxf models. The .dxf file must comply with the release 12 DXF format specifications. It should contain meshed- or closed- polyline surfaces (see the discussion below) and lines (that will be segmented by PREFEKO as discussed below).
      - Import NEC Model File
        PREFEKO supports the import of wire geometry from NEC³⁸ models.
      - Import CONCEPT Geometry File
        With this option one may import CONCEPT³⁹ geometry files
      - Import STL File
        PREFEKO can also import STL — both ASCII and binary — files. STL files supports only triangular patches and these are all imported. Also, since the STL file makes no provision for any labels, label selection is not supported. The scale factor is supported.
      - Import CADFEKO Mesh File
        CADFEKO exports the mesh to a .cfm file which is imported by an IN card in the default PREFEKO file created by CADFEKO. The options are similar to those of the other formats that PREFEKO can import. For the import of .cfm files (in addition to the mesh element inclusion/exclusion options provided) provision is made for the inclusion/exclusion of the variables that are defined in the .cfm file during the import process. Imported variables can then be referred to in other PREFEKO cards.
      - Import Feko HyperMesh File
        Import a mesh from a Feko HyperMesh (.fhm) file.
      - Import PATRAN Neutral File
        PREFEKO also supports importing PATRAN files.
      - Import ANSYS CDB File
        PREFEKO supports the import of geometry from ANSYS .cdb files. By default, when exporting such files from ANSYS, the BLOCKED option is used. PREFEKO only understands this BLOCKED syntax, the UNBLOCKED version is not supported. Also regarding the element type, only the ANSYS element types 200 (filaments, triangles, tetrahedral elements, and brick elements) as well as element type 16 (pipe16, wire with a finite radius) are supported.
      - Import ABAQUS Mesh File
        PREFEKO supports the import of mesh files from ABAQUS .inp files.
      - Import GiD Mesh
        PREFEKO supports the import of mesh files from GiD .msh files.
      - Import I-DEAS UNV Mesh
        PREFEKO supports the import of mesh files containing segments and triangles from I-DEAS UNV .unv files.
    - IP Card
      The IP card defines a number of meshing parameters as well as the wire radius.
    - KA Card
      The KA card defines an edge between two points that forms the border of the PO area. On this edge the fringe wave currents are taken into account.
    - KK Card
      The KK card defines a mesh of surface triangles in the shape of a conical section.
    - KL Card
      The KL card defines a wedge for which correction terms are added to the PO currents on two surfaces connected to it.
    - KR Card
      This card creates a mesh of surface triangles in the shape of circular region with or without a hole. It is also possible to create an elliptical region.
    - KU Card
      This card creates a mesh of surface triangles in the shape of a spherical section.
    - LA Card
      With this card, labels are assigned to segments, triangles, polygonal plates, cuboids, uniform theory of diffraction cylinders and points.
    - MB Card
      With this card, a modal port boundary condition may be applied on the boundary of a finite element method (FEM) region. A modal port essentially represents an infinitely long guided wave structure (transmission line) connected to a dielectric volume modelled with FEM.
    - ME Card
      This card must be used to distinguish the different media and to create segments and triangles (metallic or dielectric) within or on the surface of dielectrics solved with FEM or VEP as well as MoM/MLFMM.
    - NC Card
      This card defines the name to be used for the next configuration.
    - NU Card
      This card defines surface triangles representing a NURBS surface.
    - PB Card
      This card can be used to generate a section of a parabolic reflector as shown in the figure on the card.
    - PE Card
      This card defines the unit cell for a periodic boundary condition (PBC) calculation. The phase change between cells is specified with the PP card.
    - PH Card
      The PH card creates a triangular or quadrangular plate with a circular or elliptical hole as shown in the card. The hole can be used, for example, to attach a cylinder (ZY card) to the plate and it can be filled with the KR card.
    - PM Card
      A surface mesh of triangles in the shape of a polygon is created by using the PM card. The PM card also allows the specification of interior mesh points. The PM card should generally be used in favour of other cards that create flat surface meshes with straight edges.
    - PO Card
      The PO card the application of the physical optics approximation is possible.
    - PT Card
      This card defines a port connected to the full wave model. Reference this port when defining sources, loads, networks and transmission lines.
    - PY Card
      The PY card defines (by specifying the corner points) a polygonal plate surface to which the UTD formulation is applied.
    - QT Card
      This card is used to create a dielectric or magnetic cuboid, meshed into smaller tetrahedral volume elements solved with the VEP or FEM.
    - QU Card
      This card creates a dielectric or magnetic cuboid, meshed into smaller cuboidal volume elements, for solving with the volume equivalence principle in the MoM.
    - RM Card
      The RM card provides a sophisticated remeshing and adaptive mesh refinement facility. Most types of meshes (surface mesh with triangular patches, wire segment mesh, cuboidal volume elements) created by any option supported in Feko (for example, direct creation in PREFEKO with cards, but also import from NASTRAN, FEMAP, PATRAN and the rest) can be used as a basis, and one can then apply either a local or a global mesh refinement. Unfortunately in Feko Suite 5.4 there is still a restriction that tetrahedral volume elements as used for the FEM cannot be refined with the RM card.
    - SF Card
      This card scales the geometric data.
    - SL Card
      This card defines, for the combined MoM/MTL, the transitioning point from circuit elements (defined in a cable schematic) to the full wave model (defined using DP cards).
    - SY Card
      This card defines symmetry planes to reduce computation time and to reduce the number of elements to be meshed.
    - TG Card
      With the TG card, the already entered geometric elements (triangles, segments and the rest) can be translated, rotated, mirrored and/or scaled. It is also possible to duplicate structures.
    - TO Card
      Using the TO card a surface mesh in the form of a toroidal segment can be generated.
    - TP Card
      With the TP card points (previously defined with the DP card) can be translated, rotated and/or scaled (relative to the origin).
    - UT Card
      This card defines the parameters for the uniform theory of diffraction (UTD) for polygonal plates and cylinders, faceted UTD for curved surfaces and ray launching geometrical optics (RL-GO).
    - UZ Card
      The UZ card is used to create a cylinder that will be solved with the uniform theory of diffraction (UTD).
    - VS Card
      This card specifies known visibility information (required when using physical optics with multiple reflections) to reduce the calculation time.
    - WA Card
      The WA card is used to define all windscreen antenna solution elements. This would include all elements in close proximity to the finite glass structure and can consist of either segments or triangles (all defined by labels).
    - WG Card
      The WG card is used to create a wire grid in the shape of a parallelogram.
    - WR Card
      The WR card is used to define a dielectric windscreen reference plane. Geometrically this surface is not part of the electromagnetic model and is used simply to determine the curvature factor between the two elements on the windscreen.
    - ZY Card
      This card defines a surface mesh in the form of a cylindrical segment.
  - Control Cards
    Control cards are used to specify requests and solver settings and are placed after the EG card in the .pre file.
- How-Tos
  A collection of how-tos are included that covers advanced concepts.
- FAQ
  A collection of frequently asked questions (FAQ) relating to advanced concepts are included.
- Troubleshooting
  Common problems that you may encounter are discussed as well as their solutions.
- Meshing
  When meshing a model, you can either use the automatic meshing algorithm to calculate the appropriate mesh settings or you can specify the mesh sizes. When you specify the mesh sizes, the mesh sizes should adhere to certain guidelines.
- SAR Standards
  Feko makes use of a local peak SAR algorithm.
- Solution Control
  Control the execution of Feko by specifying the memory management and environment variables.
- Read MAT, LUD, RHS and STR Files
  The .mat file, .lud file and .rhs file are not generated by default, but can be read externally.
- Integration With Other Tools
  Feko integrates with various products within Altair HyperWorks Products such as HyperStudy. Integration with third-party products is also supported through the powerful scripting and plug-in infrastructure.
- SPICE3f5
  Use the correct structure, convention and syntax for a SPICE circuit definition in Feko.
- List of Acronyms and Abbreviations
  View the list of commonly used acronyms in Feko.
- Summary of Files
  Feko creates and uses many different file types. It is useful to know what is stored in the various files and weather they were created by Feko and if it is safe to delete them. The files are grouped as either native files that have been created by Feko or non-native files that are supported by Feko. Non-native files are often exported by Feko even if the formats are not under the control of the Feko development team.
- Common Errors and Warnings
  A Feko Errors, Warnings and Notes Reference Guide is available as a reference for messages that may be encountered in Feko.

Import CONCEPT Geometry File

With this option one may import CONCEPT³⁹ geometry files

Figure 1. The IN - Include an external file (Concept geometry file) dialog.

Since CONCEPT uses two different files for wires and surface elements, the type of element selection is obligatory and determines the type of geometry file to be read. The only other parameters supported here are the file name and scale factor. (The CONCEPT file does not contain labels.) If the CONCEPT model contains quadrangles, they are divided into triangles.

Since wires don’t have a radius in the model files, the radius is specified with a preceding IP card. Likewise, the elements don’t have labels, and the label as specified at the last LA card before the IN card is used. If there is no LA card, the label defaults to zero.

As for the CAD models, dielectric triangles or metallic triangles which form the surface of a dielectric, are created by preceding the IN card with the appropriate ME card.

The CONCEPT files for wires are as follows

number_of_wires
x_start y_start z_start x_end y_end z_end   [number_of_wires times]

where the first integer specifies the number of wires followed by the coordinates of the start and end point of each wire. The file is completely free format — the values are just separated by white space. The surface file is

number_of_nodes   number_of_patches
x y z                                       [number_of_nodes times]
p1 p2 p3 p4                                 [number_of_patches times]

again using free format. The values x, y and z specify the node coordinates and p1, p2, p3 and p4 specify the corner nodes of the triangles (in this case p4 is 0) and quadrangles.