ADS momentum, convergence problem

Hey guys, new here hope we can get along. I'm doing my theses on hyperthermia and was hoping you could help me. I'm designing an antenna on ads momentum, that has a superstrate
Here's a picture of the antenna

here is what the layout looks like and their properties


here's the mesh I'm using

The mesh is pretty dense so as not to have convergence problems and i didn't so far, but when i changed my antenna to alter its resonance frequency and changed the frequency range to be able to see it, momentum wouldn't converge (i think, it said "S parameters show unphysical values for certain frequencies")

I'm not entirely new to momentum I've designed antennas on it before, anyway can anyone help me out. [I read a post where someone had convergence problems with his transmission line and other people told him to check the transmission line mesh, what's it do?]

Thanks in advance

What kind of port you are using? And which ADS version?

Hey dude, thanks for replying. I'm using a single mode port of Z=50Ω. And the version of the ads I'm using is 2009. But i think i resolved the problem by setting the mesh frequency from blank to twice the maximum frequency. (took a lot of time, like an hour or so, but it worked). Now I'd like to know if you can import a layout desing from ads to cst, know anything thanks in advance.

Cst can import ADS layout file.
https://www.cst.com/Content/Products/DE/ImpExp.aspx

Thanks a lot for replying guys, you make me feel welcome

You can also export your ads layout as gdsii and import in cst.