Layered Structure with Physical Optics not working?
Hi All,
I am trying to do a simulation of a layered structure in FEKO. The structure I am working with is a simple PEC face coated in 0.9 mm of human skin dielectric. The simulation is measuring the near fields around the layered face. The 0.9 mm is about 3 skin depths worth of material for the frequencies I am working at. The face is a square 100 mm by 100 mm and centered on the Y axis (The square is parallel the XZ plane) and located 240 mm away from the origin along the Y-axis. The near field measurements are along the x axis. There is an ideal electrical dipole radiating at 79 GHz at the origin of the simulation. I actually ran two simulations. One with just the PEC face and one after applying the layered substrate. Note that for the face I am using a physical optics with full ray tracing solution to speed the simulation up. I noticed that after both simulations were complete the results of the near field were extremely close to being identical which seemed fishy. Additionally when I go into postFeko and look at the simulated model the layered structures color denoting it as a layered structure is replaced with the PEC orange color. Because of this I am wondering if FEKO is correctly meshing the layered structure or if it even registers that there is a layered structure? If anyone has any thoughts or advice I would appreciate it.
Thank You,
Cole Harlow
Answers
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You mention it is a simple model. Could you please attach the cfx?
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Here is the .cfx file. This should be the correct one.
Thank You,
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The near field, sampled basically at the source, will include the contribution from the source, which will dominate.
You should enable the option 'Calculate only the scattered part of the field' for the near field.
The OUT file shows the coating is applied, not sure yet why POSTFEKO has PEC coloring.
Label Rectangle1.Face2998:
Electrically thick surface coating
Thickness of surface coating: 9.00000E-04 m
Layer = 1 Eps_r = 6.450E+00 Sigma = 3.830E+01 S/m tan(delta) = 1.386E+00
Mue_r = 1.000E+00 tan(delta_mue) = 0.000E+00
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Thank you for the suggestion, I typically run two simulations one with the target and one without, then I just do background subtraction to remove the dominating source contribution. I was slightly surprised that the layer did not have a bigger effect than it did. Because of this surprise and the PEC coloring I thought it might be a simulation error. Thank You for confirming that this was not the case and that the simulation is performing as expected.
Thank You
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The colouring according to face medium will show PEC for coatings since essentially it's still a PEC face, just coated.
However if you set the face medium to a layered dielectric, then the face is a dielectric face and colouring will be according to the layered dielectric color.
To confirm the coating, use the Highlight option.
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