# How to get s paramter from finite structure in HFSS? (metmaterial)

1. ## How to get s paramter from finite structure in HFSS? (metmaterial)

Hi guys:)

I'm studying in Metamaterial absorber.
as you know analysis for infinite array, we can use floquet port
but I want to analysis and get s parameter in finite structure like 13X13 array or curved structure

How can i get s parameter from curved surface or finite structure?

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2. ## Re: How to get s paramter from finite structure in HFSS? (metmaterial)

Welcome 1dbduddls,

I assume for an absorber the mode you're interested in is a free-space plane wave. For finite simulations, you pretty much always want driven modal simulations. In the case of the PW, you can use either a Floquet port, a standard wave port with PEC/PMC side walls, or an incident plane wave excitation.

Good Luck!

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3. ## Re: How to get s paramter from finite structure in HFSS? (metmaterial)

Originally Posted by PlanarMetamaterials
Welcome 1dbduddls,

I assume for an absorber the mode you're interested in is a free-space plane wave. For finite simulations, you pretty much always want driven modal simulations. In the case of the PW, you can use either a Floquet port, a standard wave port with PEC/PMC side walls, or an incident plane wave excitation.

Good Luck!
Originally Posted by PlanarMetamaterials
Welcome 1dbduddls,

I assume for an absorber the mode you're interested in is a free-space plane wave. For finite simulations, you pretty much always want driven modal simulations. In the case of the PW, you can use either a Floquet port, a standard wave port with PEC/PMC side walls, or an incident plane wave excitation.

Good Luck!

Thank you for answer my question

I made a structure and surround with region. and I assigned incident plane wave on top of the region
(plane wave setup
1. plane wave location : x=0, y=0, z=15 (because my region hight is 15mm)
2. Eo vector : x=1, y=0, z=0
3. k vector : x=0, y=0, z=-1 (because i want to make wave direction top to bottom)
4. Analysis : solution frequency 13Ghz and Frequency sweep :8Ghz to 12Ghz+checked 3D Field wave option check box
)

After finished analysis, I can see the Field distribution but I can't find s parameter in Result

I know i'm doing silly question but Can you help me?

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4. ## Re: How to get s paramter from finite structure in HFSS? (metmaterial)

It's actually not a silly question: incident plane wave is probably the hardest to work with; because you have to calculate the scattering parameters yourself.

The easiest route from here is to replace the IPW with a wave port on the surface you have selected. Otherwise if you're set on the IPW:

a) Set up integration equations in the field solvers to integrate power over the "Input" and "Output" faces.

b) Using the Fields->"Edit Sources" menu, you can select between incident, reflected, and total fields.

c) S11 is just 10log(ReflectedPowerInput/IncidentPowerInput), and S21 is 10log(TotalPowerOutput/IncidentPowerInput).

Good Luck!

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