CST - S-Parameters extraction from Plane wave in CST

CST Studio Suite ​​​​​​​

Hello Everybody,

I am trying to simulate a plasmonic perfect absorber using plane wave, and want to obtain the reflection and absorption parameters. The boundary conditions are set to PMC in x-, PEC in y-, and PML (open add) in z-direction, that is also the direction of wave propagation. I use frequency domain solver, and have defined Powerflow monitors which are by definition provide Poynting vector of the EM field. However, I am unable to extract the reflection and absorption parameters of the structure. Any help would be appreciated.