finite ground plane and infinite ground plane

I'm running Ansoft Ensemble simulator.
When I'm running slover , a warning appears.
That warning message is 'Finite Ground Plane Detected'.
I don't know what it means.
This happened under I don't add infinite ground plane in substrate.
IF I add infinite ground plane in substrate , this waring can't appear.
My question is what is difference between finite ground plane and infinite ground plane ?

THX

Hello :

I don't know what's your stracture exactly , but if you'r stracture has a radiation box , please explain more if your ground plane is in the radiation box or not . it is better you show your sracture.

HI

Ansoft ensemble and ansoft designer are not suitable for simulation of structures with finite ground plan.IE3D is better.

if you want to simulate microstrip antenna on finite size ground plane, you can try WIPLD, or HFSS!