Co-Axial Feed Port CST

Hi I have a circular patch attn. I was playing around with in CST 8. A waveguide port is placed on aco-axial port which feeds directly to the circular patch through the ground plate and substrate. See diagram below

AAAAAAPPPPPPPPPPPPPPPAAAA
SSSSSSSSSSSSCCCCSSSSSSSSSSS
SSSSSSSSSSSSCCCCSSSSSSSSSSS
GGGGGGGGGSSCCCCGGGGGGGGGG
GGGGGGGGGGGCCCCGGGGGGGGGG
AAAAAAAAAAWWWAAAAAAAAAA
S-Substrate
C-Co_Ax Port
P-Cirularpatch
G-ground plate
W-Waveguide or input to co-ax port
A-Air or vaccum

If I were to replace the circular patch with a dipole attn. should I still use the Co-Ax port? Would using the Co-Ax port affect the reflection of this attenn to input from "WWW", bandwidth, ect. Thank you