excitation waveguide by coax

hi !
I'm designing an adapter , and my problem is feeding waveguide by coax.
Can anyone help me to calculate the coordinates of coax feed , and length of coax feed that enter to the waveguide ?
I want parametric coordinates , in order to calculate them for each frequency.

help please !

---------- Post added at 20:14 ---------- Previous post was at 19:41 ----------

For example, 284WCAN , this is an adapter .