How to design a Half Maxwell Fish-eye lens antenna?

[Diogo84]

Hi everyone.
I'm working on a project where I intend to design a different structure of a half maxwell fish-eye lens antenna. I'm using CST for the antenna design and I'm having some difficulties in designing the following structure with the configurable dimensions:

Can someone give me some advice?
Thanks in advance...

 

[FizTop]

Geometrically that structure is easy to model. Just create multiple spheres with same center point which is offset from vertical axis, then sequentially subtract inner spheres from outer ones. Take a cross section and sweep it around vertical axis.