# 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 = 2.62 (The relative permittivity of the substrate.)
• patch_rad = 17.5 (The radius of the patch.)
• line_len = 79 (The length of the strip line.)
• line_width = 4.373 (The width of the strip line.)
• offset = 0 (The distance between the patch centre and the feed line.)
• substrate_d = 3.18 (The height of the substrate.)
• f_min = 2.8e9 (The minimum frequency.)
• f_max = 3.2e9 (The maximum frequency.)
3. Create a dielectric medium.
• Dielectric loss tangent: 0
• Relative permittivity: epsr
• Label: substrate
4. Create the circular patch.
1. Create an ellipse.
• Centre point: (0, 0, 0)
5. Create the feed line.
1. Create a rectangle.
• Definition method: Base corner, width, depth.
• Base corner: (-line_width/2, 0, -substrate_d/2).
• Width (W): line_width
• Depth (D): line_len
6. Add a planar multilayer substrate (infinite plane) with a conducting layer at the bottom.
1. Add a Plane / ground.
• Click Planar multilayer substrate.
• Thickness (Layer 1): substrate_d
• Medium (Layer 1): substrate
7. Create a microstrip port
• Click on the short edge (beginning) of the feed line.
8. Add a voltage source to the port. (1 V, 0°, 50 Ω).
9. Set the frequency.
• Continuous (interpolated) range
• Start frequency (Hz): f_min
• End frequency (Hz): f_max
10. Specify the symmetry about the X=0 plane as Magnetic symmetry.
Tip: Exploit model symmetries (if it exists) in a large or complex model to reduce computational costs.