Cst champer simulation

Hello all
I try to construct a plasma champer excited by microwave energy.
Before construction i want to simulate it with CST, first without the plasma and then ,if possibole,
with the plasma load.

The champer includes
(1) A box cavity.
(2) An ellipsoidal cavity.
(3) An antenna located in the box cavity.
(4) A rectangular waveguide to coaxial connection from box to ellipsoidal cavity

Is there anybody to help me with this ????
Thank you