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CADFEKO
CADFEKO is used to create and mesh the geometry or model mesh, specify the solution settings and calculation requests in a graphical environment.
Solver Settings
The default solver used in Feko is the method of moments (MoM) - surface equivalence principle (SEP). A solver is specified per model, per face or per region, and depends on the solver in question.
Method of Moments (MoM)
The MoM is a full wave solution of Maxwell’s integral equations in the frequency domain.
Low-Frequency Stabilisation
At very low frequencies (frequency range where the largest dimension of the model is much smaller than a wavelength), the method of moments (MoM) solution can become numerically unstable and singular.
Activating Low-Frequency Stabilisation for MoM

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.
- Introduction to CADFEKO
  Use CADFEKO to configure a solver-ready input file for Solver simulations.
- Quick Tour of the CADFEKO Interface
  View the main elements and terminology in the CADFEKO application window.
- Preferences
  CADFEKO has various default settings that you can configure to customise it to your preference.
- Saving a Model
  Store a CADFEKO model and calculation requests to a .cfx file to reopen later.
- 3D View
  3D views are used to display and interact with the model. You can zoom, rotate and pan around a 3D model using the keyboard, mouse or a combination of both. You can use a 3D mouse, specify a view or select specific parts of a model. Multiple 3D views are supported.
- Model Protection
  Protect a model with a password.
- Model Definitions
  Define the model unit, variables, named points, workplanes and the model extents for the model.
- Constructing Geometry
  Create fully parametric and complex CAD geometry using canonical structures and perform Boolean operations on these.
- Component Library
  The component library contains an extensive list of common components, such as antennas and platforms.
- Groups
  Organise geometry and mesh parts by grouping geometry and mesh in the model tree.
- Repairing Geometry
- Repairing Mesh Parts
  Mesh parts can be manipulated in CADFEKO. Basic mesh editing and fixing capabilities allow triangles to be added, removed and mesh parts to be merged.
- Importing Models into CADFEKO
  Import a CAD (geometry) model or mesh model from a wide range of industry formats into CADFEKO to save time and development costs.
- Exporting Models from CADFEKO
  A CADFEKO model can be exported to a variety of industry standard geometry and mesh formats to be used in other applications.
- Field/Current Data
  Define field or current data using either far field data, near field data, spherical mode data or PCB current data. Use the field/current definition when defining an equivalent source or a receiving antenna.
- Defining Media
  Define a medium with specific material properties, import a predefined medium from the media library or add a medium from your model to the media library.
- Applying Media Settings
  Defined media can be applied to the model in various ways. Some media settings are applied to regions, others on faces and wires. The rules for defining media varies between the different solution methods.
- Periodic Boundary Condition (PBC)
  Use a periodic boundary condition (PBC) to analyse infinite periodic structures. A typical application of PBC is to analyse frequency selective surface (FSS) structures.
- Finite Antenna Arrays
  Create an arbitrary finite antenna array that consists of an array of contributing elements, either with direct feeds for each element or via indirect coupling, and solve with the efficient domain Green's function method (DGFM).
- Windscreen Tools
  Use the windscreen tools to define a curved reference surface constrained by a cloud of points, normals and optional U′V′ parameters. The constrained surface is then used as a reference to create a work surface where windscreen layers and curved parameterised windscreen antenna elements can be created.
- Cables
  Many electromagnetic compatibility and interference problems involve cables that either radiate, are irradiated or cause coupling into other cables, devices or antennas. Use the cable modelling tool and solver to analyse the coupling and radiation.
- Solution Frequency
  For a frequency domain result, the electromagnetic fields and currents are calculated at a single frequency or frequency range. When the finite difference time domain (FDTD) solver is used, the frequency must be specified to convert the native time domain results to the frequency domain.
- Power
  The excitation of an antenna is normally specified as a complex voltage, but it may be useful to specify the total radiated or source power instead. The result is then scaled to yield the desired source power level.
- Ports
  A port is a mathematical representation of where energy can enter (source) or leave a model (sink). Use a port to add sources and discrete loads to a model.
- Sources
  A source is used to excite or illuminate the model and cause current to flow.
- Loads and Non-Radiating Networks
  Complex feed networks can be simplified by including them as a circuit representation using general network blocks.
- Multiple Configurations
  Perform multiple solutions for a single model using multiple configurations. Multiple configurations remove the requirement to create multiple models with different solution requests.
- Requesting Calculations
  Before running the Solver, define the output requests and view in the model tree (Configuration tab).
- Infinite Planes and Half-Spaces
  Use an infinite plane or half-space to model a ground plane efficiently. The number of triangles in the model is reduced as the ground plane is not discretised into triangles.
- Meshing the Geometry / Model Mesh
- Domain Connectivity
  Domain connectivity approach allows meshes of specific parts to be treated as if connected during MoM and MoM/MLFMM solutions in places where the borders of the meshes are close together, even if the mesh vertices on those borders are not coincident.
- Working with CADFEKO Models in EDITFEKO
  A CADFEKO.cfm file can be imported into EDITFEKO to make use of more advanced features available in EDITFEKO and to directly edit the .pre file for more flexible solution configurations.
- Validating the CADFEKO Model
  During the design process, the development of a model can introduce a range of issues that can lead to a non-simulation-ready model. Use the validation toolset to verify that the model is simulation-ready or to search, detect and flag discrepancies.
- Solver Settings
  The default solver used in Feko is the method of moments (MoM) - surface equivalence principle (SEP). A solver is specified per model, per face or per region, and depends on the solver in question.
  - Defining Symmetry in the Model
    Define and exploit the symmetry in the model (where applicable).
  - General Solver Settings
    General solver settings are available that relate to geometry tests and data storage precision.
  - Advanced Solver Settings
    Advanced solver settings are available to reduce the memory footprint or speed up a solution for specific types of models.
  - Store and Reuse Solution Files
    For large models, the runtime can be reduced if the solution coefficients are saved during the solution phase and re-used in a subsequent solution.
  - Method of Moments (MoM)
    The MoM is a full wave solution of Maxwell’s integral equations in the frequency domain.
    - Surface Equivalence Principle (SEP)
      The default solver in Feko is the method of moments (MoM) using surface equivalence principle (SEP).
    - Volume Equivalence Principle (VEP)
      Volume equivalence principle (VEP) is an extension to the method of moments (MoM) for the modelling of dielectric bodies. The regions of such bodies can be arbitrarily shaped and are discretised into tetrahedra.
    - Higher Order Basis Functions (HOBF)
      Higher order basis functions (HOBF) use higher order polynomial basis functions to model the currents on any particular mesh element.
    - Characteristic Basis Functions Method (CBFM)
      Characteristic basis functions are special basis functions for the method of moments defined on large domains (blocks) that contain large numbers of sub-domains meshed into triangles.
    - Low-Frequency Stabilisation
      At very low frequencies (frequency range where the largest dimension of the model is much smaller than a wavelength), the method of moments (MoM) solution can become numerically unstable and singular.
      - Activating Low-Frequency Stabilisation for MoM
    - Numerical Green's Function (NGF)
      In the solution of large electromagnetic problems solved using the method of moments (MoM), sometimes a considerable part of the geometry remains unchanged, while only a small part changes. The unchanged part (static interaction matrix) can be saved to a .ngf file and reused to reduce CPU time.
    - Defining an Aperture in an Infinite PEC Plane
      Model a slot or aperture in an infinite plane using the planar Green's function aperture. The aperture is discretised instead of the surrounding ground plane, reducing the number of triangles and run time.
  - Multilevel Fast Multipole Method (MLFMM)
    The multilevel fast multipole method (MLFMM) is a current-based method applicable to electrically large structures.
  - Modifying the Integral Equation Method
    When using the MoM or MLFMM solution method, you can specify the integral equation to obtain faster iterative convergence.
  - Adaptive Cross-Approximation (ACA)
    The adaptive cross-approximation (ACA) is a fast method, similar to multilevel fast multipole method (MLFMM). The method improves the solution of certain complex method of moments (MoM) problems using less memory and run-time.
  - Finite Element Method (FEM)
    The finite element method (FEM) is a volume meshing technique used to model electrically complex or inhomogeneous dielectric bodies.
  - Physical Optics (PO) and Large Element Physical Optics (LE-PO)
    The physical optics (PO) solver is an asymptotic high-frequency numerical solver based on currents. Use the method in instances where electrically very large metallic structures are modelled.
  - Ray Launching Geometrical Optics (RL-GO)
    The ray launching geometrical optics (RL-GO) solver is a ray-based solver that models objects based on optical propagation, reflection and refraction theory.
  - Uniform Theory of Diffraction (UTD)
    The uniform theory of diffraction (UTD) is an asymptotic high-frequency numerical solver. The method is typically used for electrically extremely large PEC structures.
  - Finite Difference Time Domain (FDTD)
    The finite difference time domain (FDTD) solver is well suited to modelling inhomogeneous materials and models with wide bandwidths.
  - Dielectric Surface Impedance Approximation
    The dielectric surface impedance approximation is a solution method that can be applied to homogeneous, lossy dielectric regions. Use the solution method to compute SAR values for a homogeneous phantom.
- Component Launch Options
  Specify the command-line parameters for the Feko components.
- Tools
  CADFEKO has a collection of tools that allows you to quickly validate the model, for example, perform calculations using a calculator, measure distances, measure angles and export images.
- Model Tree Icons
  View the list of icons that may be found in the model tree.
- Details Tree Icons
  View the list of icons that may be found in the details tree.
- Math Functions in CADFEKO
  View the list of supported math functions.
- Files Generated by CADFEKO
  View the files associated and generated by CADFEKO.
- Default Shortcut Keys
  View the default shortcut keys available for CADFEKO for faster and easier operation of CADFEKO.
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.

Activating Low-Frequency Stabilisation for MoM

For very low-frequency method of moments (MoM) solutions, enable low-frequency stabilisation to ensure a valid solution over the full frequency range.

On the Solve/Run tab, in the Solution Settings group, click the Solver Settings icon.
On the Solver Settings dialog, click the General tab.
Under Low frequency modelling, select the Activate low frequency stabilisation for MoM check box. From the drop-down list, select one of the following:

Auto

This option allows the Solver to determine automatically if the low frequency stabilisation should be used for the model.

Always on

This option enables the low frequency stabilisation for the model.

Figure 1. A snippet of the Solver settings dialog (General tab, Low frequency modelling group).
Click the OK to close the dialog.