Anyone know how to simulate antenna and used matching network together with CST

Hello everybody,
anyone know how to simulate the antenna with matching network included
in CST simulation.Currently i am doing multiple helical antenna but want to used matching to drift the resonance back to the correct resonance because of limitation size.
rgds,
kyg

You can simulate the antenna in Microwave studio and then use add your external cct in Design studio.

Add external cct. Meaning that i need to draw the outside the antenna?
Can I compare the RL before adding and after add the matching ?
How about the port setting is that same?

I do not understand what you mean by "draw outside the antenna". You can draw the antenna inside "Microwave" studio. Once you run simulation, you can see the RL on the result tree without the matching network. There is a macro that will allow you to plot the Z-matrix. Perhaps if the normalize port to 50 ohms is on, untick it. Once you have the results in Microwave studio, you can see a box with a picture of you antenna in a box in "Design" studio. I assume your matching network is some passive LC components. You can add these LC components in Design studio to look at RL with the matching network in place.