Modeling a Center-Driven Dipole with CST

Geometry and setup

Geometry: L= 1 m, a = 0.5 mm
Model parameters:
  • Frequency: 50 MHz ~ 400 MHz
  • Steady state accuracy limit: -60 dB
Mesh definition:
  • Mesh type: Hexahedral
  • Mesh density control: Lines per wavelength = 30, Others = Default
  • Special mesh properties:
    Refine at PEC/lossy metal edges by factor = 6, Others = Default
  • Automesh
Excitation: Discrete port (1 W, 50 ohms)

download input geometry

Simulation result

Simulation time: 12 secs
Number of mesh cells: 3600
Excitation duration: 2.031171e+001 ns
Calculation time for excitation: 4 secs
Number of calculated pulse widths: 3.49899
Simulated number of time steps: 8988
Maximum number of time steps: 51374

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

  • Mesh density control: the minimum Lines per wavelength is 30.
  • Special mesh properties: 6 or greater value is needed for 'Refine at PEC/lossy metal edges by factor' to obtain higher accuracy.


  • Adding the source requires a gap between the two wires. What is the source gap length?

    In this model, the interval between two antenna parts is 1 mm.
  • What if we model the dipole as a flat ribbon?

    Substituting a 2-mm flat ribbon for a 0.5-mm radius round wire is not allowed in this model.

Screen shots

enlarge this image
Simulation Model
Fig. 1. Simulation model
enlarge this image
Simulation Meshes
Fig. 2. Simulation meshes
enlarge this image
Input impedance plot
Fig. 3. Input impedance
enlarge this image
input impedance at first resonant frequency
Fig. 4. Input impedance at the first resonant frequency