Boundary 'PerfectE1' and boundary 'Rad2' overlap

Hi,

Can some one please help me for this.
I have this design of 2x2 patch antenna array .I made all of this.

i assigned ground plane as boundary "perfectE1" and instead of creating a box for radiation i made region of lamda/4 length and assign it as rad.

now i am getting error of Boundary "PerfectE1" and boundary "Rad2" overlap

also even if this is warning.when i go to results,i get blank sheet at S11.please someone guide me



its urgent.can someone guide me please

In get rid of this warning, you can assign Rad boundary to all surfaces of the air box except for the surface corresponding to the ground plane.