Lens Design 60GHz Radar

I’m trying to design a lens for a 60GHz radar chip however rather than focusing the radar beam I’d like to widen it to a specific width. Also, the radar antenna has a main beam width that is larger in the H plane than in the E plane. If possible I’d like to change the beam width in each plane independently.

Can anyone recommend a "cook book" of lens designs or other references that would help me design such a lens?

I spent a bit of time looking at the lensmakers equation but it’s not apparent to me how I’d achieve a specific beam width with it. If there’s a way, perhaps someone could explain it to me.

Thanks!