Mushroom EPG dimension

Hello

As I said before I am a student and I AM IN very new steps for antenna design.

I have a 2*2 microstrip antenna that working frequency is 10 Ghz.

Now I want to use mushroom EPG to reduce sll(side lobe level) in the first steps I don?t know how should I select the dimension of mushroom EPG?

Width of mushroom EPG ?
Height of mushroom EPG?
Radius of via in mushroom EPG?

before any thing thank a lot

Sievenpiper's dissertation and associated papers will help

Have Fun