how much deembed distance for floquet port in HFSS should be?

Can any one tell me that how much deembed distance for floquet port in HFSS should be kept for good simulation results in HFSS.

Is there any rule for this distance or on hit and trial base.

Hi,

Could you please show how is your design?? In many cases, the deembeding is till the beginning of the metal parts in your design, or just the beginning of your design, even though it is only dielectric. The thickness of your design is also referred as effective thickness, since it usually is bigger than the physical thickness. Just take a reference for your designs, and use the same for the other designs.

Regards,

Pere

Thanks for answering!

The design consists of two FR4 layers of thickness 1mm and between them is some other dielectric material of 30 mm thickness. The metalic part is above the FR4 materials on top and bottom of the whole sandwich. The overall height of the structure becomes 32mm; width 15 mm along the x-axis and length is also 15mm along y-axis. The radiation box size is 39mm along z-axis. while i am using the master- salve boundaries and flouqent port. The deembed distance i am using is 4mm till the metal surface in the design.

Now tell me what should be the deembed distance in this case??? That i would get the relible results.

Hi Muhammad,

The deembedding distance should be like 7 mm, that is 39 mm (max height in z dimension) minus 32 (maximum height of your design), or 3.5 mm if you have a transmission design, and your design in centred along z with the airbox.
However, I would recommend you to fairly increase the airbox along z dimension, in order to avoid some nearfield ressonances (keep the excitation port far away from the surface of your design).

Regards

you recommend me to use 7mm deembed distance for the dimensions that i wrote in above post!

I also now that the this distance starts from the the top or bottom of the air box and till the metallic surface starts above the dielectric substrate. Now tell me what are the normal conditions for the height of air box i.e. what would be the top distance from the metal surface.

Is there any relationship for setting the deembed distance like in case of antenna the air box boundary starts lembda/4 from the substrate and this distance is equal from all the sides.


secondly you mention in the last answer (post) about the transmission design kindly tell me some thing about that.
Thanks

Hi,

There's no relationship between the design thickness and the airbox height. I would recomend you to leave a couple of lambdas, in order to let the attenuation of the reactive fields generated on the metallic surface when the incident wave impinges it.

I don't know how is your design (reflection/transmission), so I can't say anything about it. It was only a matter of deembeding distance, that is, 39-32 mm in case of reflection only design, and (39-32)/2 mm in case of reflection/transmission design.

Pere

Hello i have vary the deembed distance for the flouet port in my design i.e band stop filter ( FSS) also the air box height but the result is convergence does not achieved if i increase the deembed distance at 4 mm deembed distance the design converges in 9 passes but if i increase the deembed distance to 8mm or 10 mm or above design does not converge even 18 passes . What do you suggust me in this situation??

Hi,
I want to simulate a unit cell just like his, can you help me and tell me how should I design the air box and define master slave boundaries and floquet port to have two-orthogonal - polarized excitation?

Hi Muhammad Idrees,
I also want to understand about Floquet Port and how to assign Master-Slave Boundaries. I also read document for Ansoft company but I haven't understand yet.
Is this possible to use Flotque Port to simulate Unit cell SRR of Metamaterial structure?

Do you have any helpful document or any example? Plz.

Many thanks

I have attached the file here with assigned boundaries (master and slave).You can also vary the deambed distance along with the airbox according to your requirements but in this file boundaries are assigned just design your project and simulate.Secondly you can download HFSS user Manual by ansoft or i think so you can google like "floquet Ports in HFSS" some results will be appeared you can download and start work.

Hi muhammad,
Thank you for your attachment. my design is just like yours. But maybe I don't know how to interpret the results. I want to get magnitude and phase of S21. but what I get from my simulation are like this: S(Floquetport1:1, Floquetport1:2). Do you know which one of these means S21?



And another important question is that I want to exciter the unit cell with two orthogonal polarized waves. so what should I choose for the floquet port properties (modes) ?
Thank you