Why is an inverted (concave) dome on this list if a conventional (convex) dome is not unless made of diamond or horn-loaded, and leaving out 'soft' domes unless configured as a "ring radiator"? Too arbitrary to be meaningful IMO.
[I'm deleting the rest that originally followed the above and reposting it in a new thread.]
[I'm deleting the rest that originally followed the above and reposting it in a new thread.]