Since I seemed to have lit the fuse on the 3D printing of antennas, I guess that the next level is to understand some of the manufacturing constraints as well as the electrical design constraints.
This article presents some of the limitations of 3D printing of antennas and waveguide : https://www.aerodefensetech.com/component/content/article/adt/features/articles/37095
This is just a primer to get to know the basic limitations before getting started.
If you don't receive the email within an hour (and you've checked your Spam folder), email us as confirmation@grabcad.com.