capacitor for ltcc
You will have to post a picture with the model to get a correct answer.
You may need to use a lumped port. I've seen a snapshot of an example where the filter feed was perpendicular to the ground plane. You have two options in this case:
1) Draw the feed of the microstrip of the test board and put a regular waveport on the microstrip.
2) Make an artificial small hole in the ground plane near the filter feed and put a lump port between the feed and the ground plane.
Itai