CST at least one propagating mode is not considered at Port 1

Hey all,

I am performing a CST simulation of a coplanar resonator. When increasing the dielectric constant of the underlying substrate from 10 to 100 I get a warning at frequencies about 20 GHz, namely "at least one propagating mode is not considered at port 1".
What does this exactly mean?

And another, quite basic question, what exactly is a mode in the nomenclature of CST?
Do they mean the physical modes like TEM?

Best regards,

ychy123

Hi,
As you increase the dielectric constant, the modes number increase too. It means there are more than 1 mode propagating in your resonator. So, you have to increase the number of modes in that simulation, what can be done within port1 properties (Number of modes).
Regarding the mode nomenclature in CST, it is the same from EM theory. You can have TE, TM, TEM and QTEM modes depending on the simulated geometrical structure. You can simulate only the port modes checking the box "Calculate the port modes only", and you will see what kind of modes that port has.
Regards.