# 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. Define the following variables:
• freq = 100e6 (The operating frequency.)
• d = 0.004 (Plate thickness.)
• a = 2 (Width of plate.)
• b = 1 (Depth of plate.)
• epsr = 7 (Relative permittivity.)
• tand = 0.03 (Loss tangent.)
• thetai = 20 (Zenith angle of incidence.)
• phii = 50 (Azimuth angle of incidence.)
• etai = 60 (Polarisation angle of incident wave.)
2. Create the thin dielectric sheet.
1. Create a dielectric with the relative permittivity set to epsr, dielectric loss tangent to tand. Rename its label to substrate.
2. Create a single-layered dielectric.
• Label: thin_dielsheet
• Thickness: d
• Dielectric material: substrate
3. Create a rectangular plate centered at the origin in the XY plane.
1. Create a rectangle.
• Definition method: Base centre, width, depth
• Base centre: (0, 0, 0)
• Width: a
• Depth: b
4. Set the face medium of the rectangular plate to thin_dielsheet.
5. Add a single incident plane wave source from direction θ=thetai and ϕ = phii. Set the polarisation angle to etai.
6. Set the frequency to freq.

The model geometry is symmetric about the 3 principal axes, but the source is not symmetrical.

1. Specify the symmetry about 2 principal planes:
1. X=0: Geometric symmetry
2. Y=0: Geometric symmetry
Tip: Exploit model symmetries (if it exists) in a large or complex model to reduce computational costs.