1. draw the cylindar
2. add a relative coordinate system where you want to split the cylindar
3. Edit -> split, divides a solid along a plane, be sure to select the plane you want the split on and check the box to keep both halves.
4. Assign material to each section seperately.
done.
Thanks for your help. I also want to know that can i do water flow measurement in HFSS, basically I have placed two antenna in a Cylinder i want to detect flow of water as water flow S21 and S11 will be change. So i just want to know how can i make water flow in HFSS.
You can't do flow down the tube in HFSS. Ansys Fluent can be used for flow, but I don't think you can integrate the solutions.
You can do a parametric sweep for static cases with different water levels. Assign a variable to the coordinate system value that you used to split the cylinder, and use that as your parametric sweep variable.