CST Cross Pol Problems? Ludwig 3

I'm an antenna designer, i use cst 2006 in my designs and i can't reduce my cross polarization levels in my array of 8 patches grounded with 120 degrees of aperture with phase and amplitude tappers.
I use Ludwig 3 tool, but my results in practical implementations do not close to my simulations.
Wimax antenna
Freq: 5.72-5.85 Ghz
3 dB Apperture: 120 degrees
Sidelobe level : > 20 dB
F/B > 30 dB
Cross Pol: > 20 dB
Help!

try to lower your circuit to the ground ,
try to work on theener substrate,
make some slits at the sides of the patch along the e-field.

High cross-polarized response in patch arrays is often the result of leakage from the feed network. You might want to examine that area and see what you can do to minimize the stray radiation. If you are using microstrip lines you might consider CPW or stripline structures. You might also have some luck with RAM materials and shields.