How can I do Characteristic mode analaysis correctly in this antenna?[ FEKO-2023.1]

sswh2 · 2025-07-07T23:51:20+00:00

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Hi,

I am trying to perform a characteristic mode analysis for this conformal antenna, but every time I finish the simulation in postfeko, I see a warning that "This mode was not calculated over the entire range, more modes should be requested." This issue occurs every time I request more modes. How can I get the result properly? I am attaching here my simulated model. Thanks in advance!

half_arc_a_46.98_final_probe_CMA_check.cfx

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Evan_Urban

Hello,

I believe one thing you can try is request more frequency points, or a broader frequency range to compute more of the modes.

I will take a look at your model, but looks like it may take some time to get simulations run.

Respectfully,
Evan

Evan_Urban

@sswh2, sorry for the late response. This should be fixed by adjusting the frequency appropriately to effectively model the modes. This will require a finer resolution, or wider resolution.

Evan_Urban

@sswh2 increase the number of discrete points you are sampling for frequency. For example 150 frequency points instead of 100 that you have within your model. There needs to be enough frequency points within your frequency band to adequately model the modes.

Also, I want to mention the mode tracking may fail if the frequency band is too big, so it may be useful to use a smaller bandwidth.

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Evan_Urban

Hello,

I believe one thing you can try is request more frequency points, or a broader frequency range to compute more of the modes.

I will take a look at your model, but looks like it may take some time to get simulations run.

Respectfully,
Evan

Zeina

@sswh2 , adding to what @Evan_Urban has mentioned, it is recommended to use "Fine" meshing when running CMA. You will see warnings in your runs recommending that if you are using "Standard" mesh.

sswh2

@Evan_Urban sir thanks for your reply. I tried with "continous" frequency range and fine meshing but then I got error; therefore, I chose discrete frequency points. Okay, I will wait for your simulated model.

sswh2

@ZeinaI mam already did fine meshing with this file after that I posted it here same warning in postfeko. Thanks for your suggestion though.

Zeina

Great. At least you now have a better suited mesh.

Evan_Urban

@sswh2 the simulation had finished with 1000 frequency points, however I am still receiving your original issue. I will try to increment it a bit higher and see if the results change.

sswh2

@Evan_Urban sir, can you please tell me how to fix this issue?

Evan_Urban

@sswh2, sorry for the late response. This should be fixed by adjusting the frequency appropriately to effectively model the modes. This will require a finer resolution, or wider resolution.

sswh2

@Evan_Urban Sir how to do that? Can you please show me?

sswh2

@Evan_Urban sir thanks!