I'm designing an FSS in CST MWS that should be providing maximum reflection for the band (12 to 15)GHz and hence minimum transmission to this band. I've got the results has shown here. How do I find the return loss and transmission loss? Out of these 8 data legends like SZmax(2),Zmax(2), which are the return loss (S11) and transmission coefficient (S21)? By transmission coefficient, forward transmission coefficient is meant. Floquet port model is used. Fig.1 S-parameter output Fig.2 CST port illustration
According to the CST MWS help page on FSS, it is mentioned that the reflection is specified using SZmax(1),Zmax(1) while the transmission is specified using SZmin(1),Zmax(1). When the magnitude of the reflection is greater than the transmission by a fair margin, then the designed FSS is said to function as a ground plane for the designed band.