September 22, 2023 at 2:09 pm
Aymen Mzoughi
Ansys Employee

You are trying to make a test for a structure from the paper you mentioned, but the pictures above explain little about the problem.
PEC is not the best practice to mimic superconductors. Resulting res. frequencies with PEC will be slightly higher than with a correct superconductor model.
However in general, this methodology can be successfully employed with HFSS:
https://www.researchgate.net/publication/222100999_Black-Box_Superconducting_Circuit_Quantization
https://journals.aps.org/prb/abstract/10.1103/PhysRevB.90.134504
https://www.kip.uni-heidelberg.de/Veroeffentlichungen/download/6168/pdf-6168.pdf