FEKO is a computational electromagnetics software product developed by EM Software & Systems - S.A. (Pty) Ltd. The name is derived from the German acronym "FEldberechnung für Körper mit beliebiger Oberfläche", which can be translated as "Field Calculations for Bodies with Arbitrary Surface". The software is based on the Method of Moments (MoM) integral formulation of Maxwell's equations.    and pioneered the commercial implementation of various hybrid methods such as:
- Finite Element Method (FEM) / MoM where a FEM region is bounded with an integral equation based boundary condition to ensure full coupling between the FEM and MoM solution areas of the problem.
- MoM / Physical Optics (PO) where computationally expensive MoM current elements are used to excite computationally inexpensive PO elements, inducing currents on the PO elements. Special features in the FEKO implementation of the MoM/PO hybrid include the analysis of dielectric or magnetically coated metallic surfaces.
- MoM / Uniform Theory of Diffraction (UTD) where computationally expensive MoM current elements are used to excite canonical UTD shapes (plates, cylinders) with ray-based principles of which the computational cost is independent of wavelength.
- Jakobus, Ulrich (1995). Erweiterte Momentenmethode zur Behandlung kompliziert aufgebauter und elektrisch großer elektromagnetischer Streuprobleme. Düsseldorf: VDI Verlag.
- Jakobus, U.; Van Tonder, J.J. (2005), "Fast Multipole Solution of Metallic and Dielectric Scattering Problems in FEKO", 21st Annual Review of Progress in Applied Computational Electromagnetics, Applied Computational Electromagnetics Society (ACES)
- Jakobus, U.; Van Tonder, J.J. (2005), "Fast Multipole Acceleration of a MoM Code for the Solution of Composed Metallic/Dielectric Scattering Problems", Advances in Radio Science 3, Copernicus GmbH, pp. 189–194
- Jakobus, U.; Van Tonder, J.J. (2006), "Challenges Regarding the Commercial Implementation of the Parallel MLFMM in FEKO", IEEE Antennas and Propagation Society International Symposium 2006, IEEE, pp. 95–98
- Jakobus, U.; Theron, I.P. (2003), "Analysis of Coated Metallic Surfaces with Physical Optics for the Solution of High-Frequency EMC Problems", 15th International Zurich Symposium on Electromagnetic Compatibility, pp. 257–261
- Jakobus, U.; Bingle, M.; Schoeman, M.; van Tonder, J.J.; Illenseer, F. (December 2008), "Tailoring FEKO for Microwave Problems", IEEE Microwave Magazine, pp. 76–85