Hey Sebastian Tamayo In this case they are exciting the structure with a lumped port which must be defined internal to the domain.

Here is a discussion on lumped ports vs. wave ports (https://www.researchgate.net/post/How_do_you_identify_whether_to_use_lumped_port_or_wave_port_in_a_microstrip_patch_antenna)

I agree with Adam Weidling but there are many other things to be considered, I recommend going through the discussion in the link provided by Adam Weidling hopefully you will get your answer.

You have changed the origin of the coordinates and the parameters are defined based on two coordinate origins.

Dear, Sebastian Tamayo, Dr.

First of all, thank you for your asking me.

The feed port is shielded by a perfect conductor.

So you make two layers perpendicular to a substrate plane.

Two layers are the source and shield plane.

I am so sorry to be the late reply.

Hyeonjin Lee