Farfiled calcaulation error in CST

I got this message form CST
"Parllel symmetry plane:NO farfield calculation possible"
What is the reason and how to resolve it.
Thanks

Please state the boundary conditions and setup of the model. Are there any periodic boundaries set ?
P.

I guess this is what u require:
BTW I even check with without any boundry condition
1) Bottom is ground plane
3) All other boundry conditions are set to open (add space)
Althoug i manage to get the results when i change zmin not as ground but as open with add space.
You give me your suggestions

maybe the port is not in one of the Plan XY,XZ,YZ
PL

Check the backgroung material, if its an antenna model in free space it should be Normal material with ε=μ=1, i.e. Air.
P.

I Got the problem, we need to use "add open space " instead of Gnd at Zmin
Regards

but this will change the results in case your antenna is near the ground

Hi adel_48:
Open Add spce is required in most of the Antenna (e.g verticle monople antenna, Vivaldi etc) simulation to get more accurate results.
You r quite write in saying that the results would change but the change will make them close to Meas.
:D