HFSS How to get the S parameters from a finite structure using Plane Wave

Hi!
I am trying to get the S parameters from the results retrieved from a plane wave in a finite structure. I try to put a rectangular plane in which I integrate the fields to properly get the S parameters but the results do not satisfy me. I am working on metamaterial absorbers and I need to simulate several cells to compare with the infinite case.


Thanks a lot in advance!

Hi humFdz,

Some more details are required to be of assistance. Are you integrating over the entire incident wave with the planes? To calculate S parameters, are you using

S11 = 10*log10(Scattered_1/Incident_1)
S21 = 10*log10(Total_2/Incident_1)

Are you integrating the normal component of the real Poynting vector only?

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PlanarMetamaterials said:

Hi humFdz,

Some more details are required to be of assistance. Are you integrating over the entire incident wave with the planes? To calculate S parameters, are you using

S11 = 10*log10(Scattered_1/Incident_1)
S21 = 10*log10(Total_2/Incident_1)

Are you integrating the normal component of the real Poynting vector only?

Click to expand...

Hi!
I am going to add some shotscreen to better understand the model I am using. I began with a finite PEC because the S parameters are known. In the shotscreen of the prototype is possible to see another planar plane in which the parameters S are calculated. The equations that I am using are the ones presented in the other screenshot. I split the field in Ex and Ey because I think the HFSS works when they deal with the S parameters in the Floquet Port, that is when you calculate the S11 you use S(FloquetPort1:1,FloquetPort1:1) but if you want to achive the parameter S, for example, when you transmit in "x" polarization and you want to receive in "y" polarization you use S(FloquetPort1:1,FloquetPort1:2)


Thanks for your quick answer. I am a bit stuck with that.

Hi humFdz,

Have you tried using an incident plane wave? I'm not too familiar with Floquet ports, but it looks like what you've done is correct.

PlanarMetamaterials said:

Hi humFdz,

Have you tried using an incident plane wave? I'm not too familiar with Floquet ports, but it looks like what you've done is correct.

Click to expand...

Hi!
Plane wave is used when we are dealing with waveguide, it is not the case. For that reason it is necessary to work with plane wave when you are dealing with the general finite problem as far as I know.

humFdz said:

Hi!
Plane wave is used when we are dealing with waveguide, it is not the case. For that reason it is necessary to work with plane wave when you are dealing with the general finite problem as far as I know.

Click to expand...

I'm not sure what you mean. Are you not looking for the response of this structure to an incident plane wave?

humFdz said:

Hi! I am trying to get the S parameters from the results retrieved from a plane wave in a finite structure.

Click to expand...

Yes I am looking for the response of this structure to an incident wave, but I use radiation boundary conditions to simulate a finite structure. And I use wave ports for example if I want to desgin a microstrip antenna or a waveguide or something like that. I'm not sure if you can use wave port to simulate the performance of a structure with radiation or PML boundaries.

PlanarMetamaterials said:

I'm not sure what you mean. Are you not looking for the response of this structure to an incident plane wave?

Click to expand...

Yes I am looking for the response of this structure to an incident wave, but I use radiation boundary conditions to simulate a finite structure. And I use wave ports for example if I want to desgin a microstrip antenna or a waveguide or something like that. I'm not sure if you can use wave port to simulate the performance of a structure with radiation or PML boundaries.

humFdz said:

Yes I am looking for the response of this structure to an incident wave, but I use radiation boundary conditions to simulate a finite structure. And I use wave ports for example if I want to desgin a microstrip antenna or a waveguide or something like that. I'm not sure if you can use wave port to simulate the performance of a structure with radiation or PML boundaries.

Click to expand...

Yes, this is exactly why I would investigate using an incident plane wave, not a wave port.