Creating the Model

Create the model in CADFEKO. Define any ports and sources required for the model. Specify the operating frequency or frequency range for the model.

  1. Set the model unit to millimetres.
  2. Define the following variables:
    • epsr = 2.2 (The relative permittivity of the substrate.)
    • freq = 3e9 (The centre frequency.)
    • lambda = c0/freq*1e3 (The wavelength in free space.)
    • lengthX = 31.1807 (The width of the patch in the X direction.)
    • lengthY = 46.7480 (The depth of the patch in the Y direction.)
    • offsetX = 8.9 (The location of the feed.)
    • substrateLengthX = 50 (The width of the substrate in the X direction.)
    • substrateLengthY = 80 (The depth of the substrate in the Y direction.)
    • substrateHeight = 2.87 (The height of the substrate.)
    • fmin = 2.7e9 (The minimum frequency.)
    • fmax = 3.3e9 (The maximum frequency.)
    • feedlineWidth = 4.5 (The feedline width for the microstrip model feed.)
  3. Create the patch.
    1. Create a rectangle.
      • Definition method: Base centre, width, depth
      • Width: lengthX
      • Depth : lengthY
      • Label: patch
  4. Create the substrate.
    1. Create a cuboid.
      • Definition method: Base corner, width, depth, height
      • Base corner: (-substrateLengthX/2, -substrateLengthY/2, -substrateHeight)
      • Width: substrateLengthX
      • Depth: substrateLengthY
      • Height: substrateHeight
      • Label: substrate
  5. Create the feed pin as a wire between the patch and the bottom of the substrate. Position the feed pin with an offset from the edge of the patch.
    1. Create a line.
      • Start point: (-offsetX, 0, -substrateHeight)
      • End point: (-offsetX, 0, 0)
  6. Add a wire port to the start of the line.
  7. Add a voltage source to the port. (1 V, 0°, 50 Ω).
  8. Union all parts and rename the union to antenna.
  9. Create a new dielectric medium with label substrate and with relative permittivity set to epsr.
  10. Set the region of the cuboid to substrate.
  11. Set the face of the patch and the bottom face of the substrate to PEC.
  12. Set a continuous frequency range from fmin to fmax.
  13. Specify the symmetry about the Y=0 plane as Magnetic symmetry.
    Tip: Exploit model symmetries (if it exists) in a large or complex model to reduce computational costs.