Hi thanks for the response! Yes my metamaterial is completely passive, I do not have and active components. From you statement “High passivity values close to 1 suggest that there is very little loss, which might seem contradictory if you are expecting higher losses.” I am actually expecting low material loss. Here is the full formula for calculating the radiation loss: 1 = (S11)^2 + (S21)^2 + Radiation_loss + Material_loss. If I’m interpreting the material loss as the passivity with values that are ranging from 0.99-0.97, would that not be high loss? You mentioned that “1 suggests that there is very little loss” if that is the case, I am probably interpreting the values incorrectly. If the passivity were subtracted from 1, then these values would be low enough. But if I am interpreting them as a function of my S-parameters they will give a value greater than 1. I have taken the s-parameters and passivity as a function of magnitude when graphing them in HFSS.

Could you maybe clarify this statement a bit more: “High passivity values close to 1 suggest that there is very little loss’ ‘. Also would you by chance know what units the magnitudes for passivity are?