Dual pol feeder design for a 40cm 5ghz parabolic antenna

Hello everyone,
I'm looking at how to make a dual pol feeder with decent separation for 5-6ghz band, the classic tube with dipoles would be ok, but I dont know how to do sizing/reflector for the outer dipole.

I'm also open to different designs, like cassegrain or exposed dipoles with reflector.

best regards,
Giacomo.