site:www.edaboard.com cst dispersion diagram

Dear Piboo,
I'm working on a structure similar to that of Sievenpiper's mushroom structure! Can you tell me the logic behind using the Et=0 for the zmin and zmax? And the reason for the waveguide port on zmax?

Thanks,
RF Girl

hi RFgirl,
Could you please upload your details here too? I don't think there is any copyright issue for doing so, as we all upload it here only. Thank you.
Regards
Praful

Added after 1 minutes:

I meant details of generating dispersion diagram.. :)

Hello all,

Electric boundaries are used to obtain the TE mode propagation (you can choose Magnetic boundaries to have the TM mode).

Then in the structure, the waveguide was used to predict the phase and magnitude reflexion. You don't need it for the dispersion diagram.

Hope it will help you,

regards,

Piboo

i vote piboo ,also avoiding using all E walls to prevent droping in the cutoff frequency of ur waveguide dimension

anyone can tell me how to put the two modes of frequency in the same figure(like piboo done in the 8th floor) in order to see the bandgap

thanks

hi

The number of modes is chose in the Parameter Sweep of the eigenmode solver: by selcting frequency of mode.
You have to select 1 then you select 2 and more if you want.

regards

piboo

Hello everybody!

A short time ago I also started some work on EBG structures. Actually I have been successfull at calculating the dispersion diagram of the famous sievenpiper structure in HFSS. But now I want to try it in CST.

So I downloaded the example file from piboo, which is a very good starting point. But my problem is: Why does he use an electric boundary for Zmax? Shouldn't it be something like an open boundary? (ok, not possible for the eigenmode solver in CST!) Because the electric boundary acts like PEC and reflects all the incident fields that might come from radiation of the Sievenpiper structure and therefore disturbs the eigenmode calculation!? In HFSS it is possible to use a perfectly matched layer (PML), so that all radiated fields will be absorbed.

Does anybody have an explanation?


@RFgirl
Did you solve your problem with the anisotropic unit cell?

Hi everyone, i 'm also concerned about how to get the dispersion diagram of EBG in CST (v2006B). I've posted here a paper in which the author use CST to get the diagram, but I don't know how to do that.
Thanks for help.

I am a new one here. Thank you!

When you use periodic boundary conditions, the plane wave will be out of phase with neighboring unit cells when k is not equal to zero. So, how do you define the source? Please help.

is there any tutorial about extraction of bandgap of a structure using CST ?

hello SAJ25,

There are many in this forum. The mostly used one is reflection phase diagram and S21 between the EBG. I am sure it is easy to get information in this forum. If not let me know I'll send you the links.

Regards
Praful

Hi all,can any one exlplain the simulation 3 times for each mode in CST MWS.
1 from Γ to X point of Brillion zone
2 from X to M point
3 from M to Γ point

Hi!

can someone here in the forum a model to explain how to obtain the dispersion diagram of an EBG structure, or put an example in CST please.
and read all the posts on the forum and can not get the results of the papers.
can someone help me?

Hi,piboo
How do you determine the distance between the Zmax E boundary and patch,thanx a lot.
Regards.

Hi,

Kindly if any one can provide material/example on how to compute dispersion diagram for unit cell in CST.
I am able to do it in HFSS and wants to verify my results in CST.

if there any need to put air box above the substrate if yes then what should be the height of that box ?

Good morning every one here. someone can tell me how we Add watch: Frequency of Mode 1 & Frequency of Mode 2

hi
someone can tell me how we Add watch: Frequency of Mode 1 & Frequency of Mode 2?

tnx