corrugated horn [CST]

Hi,

I want to make a corrugated horn with CST.

When i define a new material, i have the possibility to have "corrugated wall" for the type of my material. I fill the different parameters of the corrugation but I don't how i can apply this material on my conic horn. For example if i want to do this horn in copper, how i can apply my material on the surface inside the horn.

ps: the horn will work in W-Band.

If somebody can help me .

Thanks.