I have a transceiver, which uses differential ports for its RF signal, both for trans and rev. anyone to help me about the S-parameters measurement for the differential port? Thanks
If you have 4-port network, you can measure it directly.
If only the input character is cencerned, you can measure the differential port as a 2-port network and calculate out the differential S11_diff_2Z0 with 100ohm by:
S11_diff_2Z0=(s12-s22+s21+2*s11*s22-2*s12*s21-s11)/(s22+s12-2+s11+s21)