Modeling a Powerbus with FEKO

Geometry and setup

Double-sided PCB:
  • Size: 125 mm × 100 mm × 1 mm
  • Top and bottom metal: PEC
  • Dielectric: FR4, εr = 4.5, dielectric loss tangent = 0.015
  • Global mesh size: Edge length=6 mm, Segment length=0.2 mm, wire radius=0.01 mm
  • Disable volume meshing
  • Small features: default
  • Advanced: Enable mesh smoothing
  • Settings: Double precision
  • Frequency: continuous (interpolated) range:5 MHz - 2 GHz, maximum number of samples=200
  • Excitations: Voltage source (1 V, 50 ohms)
  • Calculation: Far field, θ=0° - 90°, φ=0° - 90°

Download Geometry Input File

Simulation result

Number of metallic triangles : 2187
Number of dielectric triangles: 205
Number of metallic edges (MoM): 6314
Number of basis function for MoM: 6929
Run time: 2 hours

Decisions the user must make that affect the accuracy of the result

  • Uncheck the 'Enable volume meshing' option. For the power bus problem, the MOM analysis will be accurate.


  • How can we model the powerbus model?

    Actually, there are two methods to create this double-sided PCB.

    1) Create the dielectric substrate by defining a rectangular block and assign a dielectric medium to it. Then, assign the PEC attribute to its top and bottom faces.
    2) Create the substrate block and assign a dielectric medium to it. Draw two polygons (rectangles). One touches the top face of the dielectric solid and another touches the bottom face. They are perfect conductors by default.

    The first method is the most straightforward way of doing this. The problem with the second method is that when you make a union of a dielectric block and a PEC surface that coincides with a face of the dielectric, the face may be "absorbed" into the dielectric and lose its PEC property. Thus you would have to reassign the PEC property to the face. Therefore it is recommended to use the first method.
  • Can a feed be located at the edge of the plane surface?

    In FEKO, voltage sources are not applied directly to the model geometry or mesh. A port must be defined on the geometry or mesh before adding the required source or load. In this example, the voltage source is located at one edge of the PCB. However, in FEKO, the edge for a port is not allowed to be on the surface of the dielectric.
    More information...

Screen shots

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simulation model
Fig. 1. Simulation model
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simulation meshes
Fig. 2. Simulation meshes
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input impedance plot
Fig. 3. Input impedance
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E-field plot
Fig. 4. Electric field at 3 m, θ=0°, φ=0°
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E-field plot
Fig. 5. Electric field at 3 m, θ=90°, φ=0°
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E-field plot
Fig. 6. Electric field at 3 m, θ=90°, φ=90°