# 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 = 12.5e9 (The operating frequency.)
• lam = c0/freq (The wavelength in free space.)
• lam_w = 0.0293 (The guide wavelength.)
• h_a = 0.51*lam (The waveguide radius.)
• h_b0 = 0.65*lam (Flare base radius.)
• h_b = lam (Flare top radius.)
• h_l = 3.05*lam (Flare length.)
• ph_centre = -2.6821e-3 (Horn phase centre.)
• R = 18*lam (Reflector radius.)
• F = 25*lam (Reflector focal length.)
• w_l = 2*lam_w (The waveguide length.)
2. Create the horn.
1. Create a cylinder along the Z axis.
1. Definition method: Base centre, radius, height
2. Base centre: (0, 0, -w_l-h_l)
4. Height (H): w_l
5. Label: waveguide
2. Create a cone.
• Base centre: (0, 0, -h_l)
• Height: h_l
• Label: flare
3. Union the two parts and simplify the resulting union.
4. Rename the union of the two parts to horn.
5. Delete the face at the front end of the horn to create an opening.
6. Rotate the horn by -90°.
• Axis direction: (0, 1, 0)
7. Create a waveguide port on the face at the back end of the waveguide section.
8. Add a waveguide source on the waveguide port. Excite only the fundamental mode and use the default settings.
3. Create the parabolic reflector.
1. Create a paraboloid.
• Base centre: (0, 0, F)
• Focal depth: -F
• Label: reflector
1. Rotate the paraboloid by -90°.
• Axis direction: (0, 1, 0)
2. Set the solver method for the reflector face to use LEPO - always illuminated method.
Tip: Open the Face properties dialog and click the Solution tab. From the Solve with special solution method, select Large element PO - always illuminated method.
4. Decouple the MoM and LE-PO.
Tip: Open the Solver settings dialog, click the High frequency tab and then click Decouple PO and MoM solutions.
Tip: The decouple setting will save computational resources. It is not recommended where the coupling (interaction) between the PO and MoM objects is strong.
5. Set the frequency to freq.
6. Specify the symmetry about 2 principal planes:
1. Y=0 plane: Electric symmetry.
2. Z=0 plane: Magnetic symmetry.
Tip: Exploit model symmetries (if it exists) in a large or complex model to reduce computational costs.