elements phase arrangement in CST (Reflectarray)

Hi all.

I'm working on Reflectarray.
i have designed my unit cell by CST.
after designing the unit cell i placed the cells in array form and excite it with a horn antenna.
now, each element have it's own phase in re radiating field. so we should know the element phases to compensate them to make all elements radiate in phase, but we could not determine the elements phases in CST to change them to radiate in phase.

i would be thankful if someone could help me.
thanks in advance.