Incorrect S11 resonant frequency

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So based on previous discussion, I have managed to obtain better S11 values in negative range. However, I am unable to get the correct resonant frequency.

I am not sure if it because of improper modelling, or that of wrong lumped port definition.

Based on the image below https://gusbertianalog.com/content/images/2024/11/MEAS_ROUND_CC.png

from the author of the article https://gusbertianalog.com/loop-antenna-design/

I am supposed to get the resonant frequency at 434 MHz, but instead i get it at 460 MHz.

I have uploaded the comsol file.

(P.S. I tried to upload this question, but i got a message saying i cant view this question in the forum, so i am uploading the question again. )



1 Reply Last Post 12.06.2025, 19:14 MESZ

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Posted: 1 day ago 12.06.2025, 19:14 MESZ

I know we always ask to see the .mph file. However Comsol 5.3 is really old at this point and it is unlikely that anyone will be able to open it.

However- the linked figure is experimental data, not simulation. There are many possibilities here...rounded measurements, varying insulator parameters, etc. etc. What you describe may be acceptable agreement all things considered.

You might want to check mesh size, and maybe run a study reducing mesh size.

I know we always ask to see the .mph file. However Comsol 5.3 is really old at this point and it is unlikely that anyone will be able to open it. However- the linked figure is experimental data, not simulation. There are many possibilities here...rounded measurements, varying insulator parameters, etc. etc. What you describe may be acceptable agreement all things considered. You might want to check mesh size, and maybe run a study reducing mesh size.

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