In Postfeko what is the most efficient way to plot HPBW over frequency?

tobias_from_edag · 2025-03-03T08:53:01+00:00

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Hello,

I am trying to plot the HPBW of an Antenna in Postfeko as a function of the frequency. I can show the HPBW and similar parameters in graphs, but I can't access the values for further processing in postfeko or lua.

I would like to know if there is a way to access these values.

My current goal is to plot the HPBW as a function of frequency. I would later also like to plot FNBW, and position of the main lobe as functions of frequency, so I would need to extract them, too.

I have seen this old post saying that it should be possible since version 2019, but I can't figure out how to access those derived results in postfeko.

https://community.altair.com/discussion/9567/far-field-data

Thanks

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Evan_Urban

Hello Tobias,

To find the DeriveFarFields, you can try going to your installation folder C:\Program Files\Altair\*Your Feko Version*\feko\shared\lua\DeriveResults (You can also search DeriveFarField in the installation folder). This provides the modulae that derives the far field quantity data. Using this I believe you can write a lua script that can compute the HPBW over all frequency and then plot in POSTFEKO.

Respectfully,
Evan Urban

tobias_from_edag

Hello,

I finally got the chance to look at those modules, and it seems like they only derive values like gain. I could not find a section that allows me to access the values that postfeko provides as plot output.

I ended up computing gain with the formula suggested here, and wrote my own script to manually compute the hpbw. https://help.altair.com/feko/topics/feko/user_guide/scripting/dataset_structure_gain_feko_r.htm?hl=gainfactor

I am still confused by the fact that postfeko can compute such values for display on graphs, but it seems unable to output them in numeric form.

Evan_Urban

Hello Tobias,

I was looking into this a bit and believe you can extract the values for the HPBW (I haven't done the FNBW) and this is just for one simulation frequency. It will need to be modified but I believe this helps extract the HPBW value. Let me know your thoughts or if you have questions that we can work through.

Respectfully,

Evan Urban

HPBW_Extraction_Test.lua

Evan_Urban

You can look at all of the values in the annotation1 or annotation2 by doing inspect(annotation1:GetValues()) to see what other information is stored in this table.