Irina G.
Ansys Employee

Hi, 

I personally don't like to use modes in waveports that are below the cutoff frequency. You can test if they can be de-embedded correctly. Also note that to get S-parameters that one expect to see below the cutoff frequency without renormalizing waveports, you need to switch to Power definition of S-parameters. If possible, re-formulate the design so the lumped port is used.