Reply To: Transmission values are very low during s parameter extraction

[Guilin Sun]

 

It is just a warning, meaning some of the S parameters are not reciprocal, most likely due to numerical errors. You can either modify FDTD settings with finer mesh/long simulation time with smaller auto shutoff min/increase PML thickness or number of layers etc. Or you can also ignore it because such error can be minimized later if you do converging test. Also, make sure the port/monitor collects the mode power correctly, with sufficient size but not pick up some scattering power, if any.