"Reflection/transmission not defined due to possible grating lobes "
Above is the warning of the simulation. I want to simulate a frequency selective surface (FSS) made of metal, here I use the PEC, and I search for the reason, I find the setting of nearfield may help a little, but I don't know the exact size of the nearfield settings. Maybe the one forth of the lambda at fmin is the right answer? I am not sure.
