Altair RISE

A program to recognize and reward our most engaged community members

Nominate Yourself Now!

Limited current coupling using proximity feed scheme

I have designed a patch antenna which is operated using proximity feed. After running, in POSTFEKO the realised gain was very low despite 'good' gain values. When I checked the current activity using Currents requests, I found out that only a little current is induced in the patch. I'm running FEKO 14. I have no idea what's wrong. Any help will be appreciated. Thank you.

Find more posts tagged with

English

Feko

Accepted answers

All comments

JIF

Hello Jayaprakash,

As always, I would recommend that you use the last version rather than the old version (14). But, I don't think the version is the problem. ;-)

You have not provided a model or any other information that would allow anyone to help you. Did you create the model from a paper and you are trying to reproduce the results? If so, add both the model and the reference to this issue. If not, maybe it is just not a well designed aperture feed? We have two aperture feed models in the Example guide. Is your model similar to those?

Without any more information, I can only recommend that you mesh finer around the aperture and close the the aperture (feed and patch).

Altair Forum User

Hello JIF,

Yes, I created a model from a paper and trying to reproduce the results. I created wire port for feeding.

I will now add the reference paper as well as the model now.

Please find the attached files here. The model has not yet been completely but it should be enough to know the results.

Unable to find an attachment - read this blog

Altair Forum User

Hi @Jayaprakash

The resonances that you are looking for are very narrowband, I suggest increasing the number of frequency points for your simulation, and you may very well need to run a mesh convergence. Here is the results the I got using 10MHz frequency resolution with an infinite ground and substrate, using your meshing settings.

Hope that this helps.

<?xml version="1.0" encoding="UTF-8"?>

Altair Forum User

Hello Mr.Futter,

Your suggestions are certainly very helpful and I'm running those simulations now. I'll post the results as soon as the simulation completes.

Altair Forum User

Yay!! I got the results and reflection coefficients values are very good, even though it took more or less 2 hours..

My problem is that current flow is very less which is affecting the realised gain of the antenna. I'm uploading the video which shows the current distribution in the patch.

Please do watch and provide your valuable ideas and suggestions.

Unable to find an attachment - read this blog

Altair Forum User

I would suggest viewing the current in dBs, not linear scale - it will give you a much better feeling for how the current is coupling onto the actual antenna surface

The realized gain is also affected by the antenna matching. So I would suggest checking S11 and then only look at the surface current at the resonant frequencies of the antenna.

Altair Forum User

Hello Mr. Futter,

As you suggested, I viewed the currents in dB and the results are better than I expected and I have to thank you for that.

The realised gain graph in dB, of course, has been attached. Can you please elaborate more on S11?

Thank you very much, Mr. Futter.

<?xml version="1.0" encoding="UTF-8"?>

Altair Forum User

If you plot S11 or the Reflection coefficient from the source you should see the realised gain has peaks at the same frequencies as the nulls in S11.

Altair Forum User

Will it be something like this???

<?xml version="1.0" encoding="UTF-8"?>