connect acoxial to acircular WG at 10 GHZ

hello:
I want to connect acoxial to acircular WG at 10 GHZ .
1- how ican connect?
2- what is distance from the WG edge to the probe?
3- what is the probe length inside th WG?
THANKS.

http://ceta.mit.edu/PIER/pier79/02.0....Hassani.M.pdf

check this.
this is rectangular but you will get an idea.
also check the references provided in this paper.