Analysis of Complex Cable Harnesses

CabFEK I/F is an interface between CableMod (product of SimLab Software GmbH), a 2D field solver for determination of transmission line characteristics, and FEKO, a 3D full-wave Method of Moments (MoM) based solver. The combination of the two codes enables the analysis of a unique but very important class of EMC problems, namely, the interaction between cable harnesses and their environment.

The analysis in CableMod is done through a very powerful 2D solver which determines the transmission line characteristics and a Spice -equivalent network simulator for calculating the currents and voltages along a fully three-dimensional conductor systems.

Capabilities
• Import cable harness geometry
• Library management system to store different geometries
• Automatic bundling of cable harnesses
• Parametric variation and Monte Carlo analysis
• Multiple simulation capabilities in time and frequency domain
• Various import and export options
• Single wire, coax, twisted pair, ribbon and complex cable harnesses analysis
• Voltage distribution at specific measuring points
• Current flow through components
• S-parameters
• Impedance

Motivation for hybridising Transmission Line (TL) analysis with full wave MoM technique

Full 3D MoM only:
• The TL has to be discretised
• Fine mesh required for surfaces close to the TL (both these requirements resulting in many unknowns)
• Complex multi-lead cables (bundles) and shields not possible

TL analysis only:
• Coupling with external structures only through static L/C matrices, no coupling through radiation.

For complex practical applications the solution is a combination of these two techniques. The result is not only the ability to solve this class of problem but also the very effective solution in terms of computer resources

Radiation from transmission lines (cables)
• The cable harness is analysed in CableMod, taking all loads into account. (L and C coupling matrices are solved taking the surrounding 3D geometry into account.)
• The currents and charges on the cable are then computed and passed to FEKO.
• FEKO would use these "impressed" current sources and do a 3D full wave solution of the structure.
• Near-fields, radiated far-fields, induced currents on the 3D body, or coupling to other elements such as receiving antennas can be computed.

Coupling of electromagnetic fields into transmission lines
• FEKO obtains the geometry of the cable harness from CableMod.
• The 3D structure is modelled in FEKO with some excitation (e.g. voltage source on a transmitting antenna, incident plane wave, interference source modelled as a Hertzian dipole etc.)
• FEKO calculates the electric and magnetic near-fields at discrete sample points along the cables as specified by CableMod. • CableMod imports this information, transforms it into equivalent distributed voltage and current sources in connection with a modified transmission line theory.
• CableMod is then able to compute the currents along the transmission lines and in the connected elements.

Combined Radiation Calculations with CableMod and FEKO (110 kB)

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