IE3D Finite and Infinite Ground Planes

Hi,

I am new to IE3D and am trying to learn it. I would like to use it to design PCB antennas (inverted-F, meander line, etc.).

Most examples I've read so far use an infinite ground plane. My question is: what is the difference between using an infinite and a finite ground plane?

If anybody has any examples of PCB strip antennas in IE3D, that would be very helpful.

Thanks!