help, wanna design circular patch at 10.45ghz

Hii,
I am doing my final yr grad, for my proj, m required to design a circular patch in cst, m totally new to this software,
from online info,
i have designed a cicular patch at 10.45GHz,
substrate - FR4(lossy) material
substrate height - 1mm
radius of the patch- 3.56mm
ground nd patch height - 0.1 each, PEC material,
probe radius- 2mm
feed radius- 0.3mm


when i started the solver, an error occurred showing wave guide port is too short,
can someone help me with this?

I am also a newbie in antenna design, but I doubt using FR4 at 10G, maybe you need other materials.

okay, can u suggest me other
do u have any other material in ur mind?