I am developing a system based on interferometry (diagram attached) and I don't know how to properly calibrate the system. I have a PNA 5242A and a Ecal module (N4691-60004). I had performed a 2 full port calibration before hybrid coupler but the cable contribution before DUT is quite strong, so I would like to remove it. I was thinking on doing a 1-port calibration before where DUT is placed, but I am working with S21 parameter, and I don't know how to make the transformation.
Thanks in advance and sorry for my lack of understanding.