dear dlock
let us know the specification of your antenna.
about the feeding, and what kind of type antenna that you ask? Microstrip or horn or rhobic, or what?
Your Q seems so Vague.
about the material, it depends on your antenna specification
I have made a simple antenna simulation using Copper and Brass.
As long as the thickness between Brass and copper is Same, there isn't a big difference between both of it.
If your antenna refers to some journal Please upload here. So we can see and try to help you.
Best regards.