# 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 = 30e6 (The operating frequency.)
• lambda = c0/freq (The wavelength in free space.)
• rBig = 1 (Radius of revolution.)
• rSmall = 0.1 (The pipe radius.)
• wireRad = 5e-3 (The wire segment radius.)
2. Create an elliptic arc with radius set to rSmall. Change the workplane origin to (-rBig ,0,0). Set the U vector to (0, 0, 1) and V vector to (1, 0, 0).
3. Rotate the arc over an angle of 185° around the Z axis.
4. Spin the ellipse over an angle of 350° around the Z axis.
5. Draw an elliptic arc through the centre of the toroidal section. (radius = rBig, start angle = 0°, end angle = 360°)
6. Add an incident plane wave that loops over multiple incident angles with 0°θ≤90° and ϕ=0°. Set the Polarisation (angle) to 90°. Increment the incident angle, θ, in 10° steps.
7. Set the frequency to freq.