HFSS, simulation of a single SRR to find resonant frequencies

I was wondering if anybody has experience or knowledge of how to simulate a single SRR in HFSS to find its resonant frequencies. I am not sure if wave ports would be the ideal case, and if in that case I need radiation boundaries for the region's sides or PEC and PMC. Another approach can be using floquet ports, but padding the unit cell with enough air so the whole system can be stand alone instead of a really periodic structure.

I searched a lot in the forum, but almost all of similar threads don't have any reply. So let's give it another try.

Hi violetcrow,

Find the dispersion diagram using an eigenmode simulation, similar to what you suggested using floquet ports (personally, I never use them). You can find an outline of the process in one of my previous posts. https://www.edaboard.com/threads/265560/#post1140645

Good Luck

You could simulate it with lumped port,and see where the z is 0 or infinite(it has chance to be infinite because SRR is a parallel resonator )

Thank you very much for the reply and help. I tried to use eigenmode but each time I receive this error:
"Adaptive solution setup, process hf3d error: No eigenmodes were found. This could be caused by a very lossy or very open structure, or the spectrum of modes may be nearly continuous.. "

I am not dealing with periodic boundaries, so all faces are in PML condition. The file is attached and I appreciate if you could take a look please.

PlanarMetamaterials said:

Hi violetcrow,

Find the dispersion diagram using an eigenmode simulation, similar to what you suggested using floquet ports (personally, I never use them). You can find an outline of the process in one of my previous posts. https://www.edaboard.com/threads/265560/#post1140645

Good Luck

Click to expand...

I'm just guessing, but I think that the eigenmode solver is unable to cope with all of the PMLs. My suggestion would be to put in PBCs, with a good deal of empty space in between the boundaries and the cell.

It might be the reason. I'll work more on that and when reasonable results I obtained I'd share. Thanks again.

PlanarMetamaterials said:

I'm just guessing, but I think that the eigenmode solver is unable to cope with all of the PMLs. My suggestion would be to put in PBCs, with a good deal of empty space in between the boundaries and the cell.

Click to expand...

Did you ever solve this error?????
I've been seeing the same thing in the context of microwave cavity resonances, sometimes without any PML's at all......

violetcrow said:

Thank you very much for the reply and help. I tried to use eigenmode but each time I receive this error:
"Adaptive solution setup, process hf3d error: No eigenmodes were found. This could be caused by a very lossy or very open structure, or the spectrum of modes may be nearly continuous.. "

I am not dealing with periodic boundaries, so all faces are in PML condition. The file is attached and I appreciate if you could take a look please.

Click to expand...

Not yet, I rather just testified the resonance frequencies by field intensity around the SRR. In your case I saw many topics in the forum though which you might find helpful. I was receiving the error because the region box was fairly large, and when I shrink it to less than a wavelength, the results didn't match with predictions though there were not any error in HFSS.

nevetts said:

Did you ever solve this error?????
I've been seeing the same thing in the context of microwave cavity resonances, sometimes without any PML's at all......

Click to expand...

Maybe you could post a link? I haven't been able to find anyone else dealing with this error, either on this forum or with google...

Have you seen Ansoft tutorials for eigen mode? There is a sample of cavity resonances. I upload the one I had, hope it helps.

nevetts said:

Maybe you could post a link? I haven't been able to find anyone else dealing with this error, either on this forum or with google...

Click to expand...

Yes, I'm fine with eigenmode solver and finding resonances. Its the error:

"Adaptive solution setup, process hf3d error: No eigenmodes were found. This could be caused by a very lossy or very open structure, or the spectrum of modes may be nearly continuous.. "

that I am having trouble with.
Thanks for the tutorial upload!

Would you like to upload your file, so everyone can take a look at?

For me, just shrinking the region box helped to get rid of this error, but the result was as what we were expecting.

I am getting an almost correct result using eigen mode solver for SRR structure. But the eigen frequency corresponding to first phase value is always incorrect. Did anyone face the problem? Kindly reply.

purushothaman said:

I am getting an almost correct result using eigen mode solver for SRR structure. But the eigen frequency corresponding to first phase value is always incorrect. Did anyone face the problem? Kindly reply.

Click to expand...

Hello, I am trying to make almost the same simulation, finding eingen frequencies with FEM eigenmode simulation of just a single SRR. I want to do this, in order to compare the results of the simulation of a single SRR magnetically-excited by a microstrip line and measuring the resonant frequency through the transmission coefficient.

Currently, I am using EMPRO, from agilent (now Keysight). In this software, I think this type of simulation works different, at least the settings. I have to use PEC walls as boundaries, no PML is allowed. Also, I have not seen how to set Master/Slave conditions in EMPRO.

Curerntly, I am having problems of the correct eigenmodes, since they seem to vary very much with the size of the vacuum box. I would like to participate in this discussion i order to gain confidence on my results, or to know if I would have to migrate to HFFS as well.

Thanks.