which kind of port should been chosen in the IE3D 10.0?

hellow everyone,
now i am designing a low pass filter with stripline, and the pec traces are on the both side of the stripline. i want to simulate it with IE3D, but i don't know which port should been chosed, i need you help, thanks :>

you must select port for edge group.

in the ie3d ,there are 6 kinds ports, i don't know which port is suitable. and i have tried the vertical localized, and the negative levels is 2.254mm, the positive level is 4.254mm,when the software is running, it prompt the distance is too big, what should i do, please help me:<, can you instruct in detail?