I was on a Sperry team designing and
building these for marine radar at 9375MHz many
years ago. The milling of the edge slots (or as
well the broadside slots) is quite critical in order
to keep the gain up and the sidelobe level low.
Also you need to consider the array illumination
function most appropriate for your application.
This might be Tchebychev, cosine-on-pedestal etc
each of which has a specific beamwidth and sidelobe
I have a few designs ready-done
(by others) for 10.3GHz.
What are your design
criteria, like operating bandwidth, gain, sidelobe
level, polarization etc?
Is this a student project
or a commercial product?