# problem recognizing floquet modes in CST example simulation

#### yef smith

Joined Aug 2, 2020
359
Hello , i am, trying to build a beam splitter in CST.
basicly what this means the we have an incident wave on some structure shown bellow, the structure cancels the specular reflection while creating two new beam at a constant angle which represent the floquet modes of order 1.
I have tried tried to build it as shown bellow.
where i set 6 floquet modes:
In normal CST in waveguide port when we set 6 modes then we get 6 modes excitation results in the s-parameters.
Here i see only two odes instead of 6.

but i dont see the 6 floquetmodes i defined?
where did i go wrong visualising floquet modes.
Is there somwone who has simple example i could simulate?
Thanks.