From S-parameters to T-parameters
In matrix form, the formula is
T=([0100]S+[1000])([0010]S+[0001])−1
While for each element, we obtain
T11T12T21T22=S211=−S21S22=S21S11=−S21S11S22−S12S21
The formulas are obtained with the methods explained here.
The MATLAB implementation can be found in circuitconversions on Gitlab.
Definitions
[B1B2]=S[A1A2] | [A1B1]=T[B2A2] |
The incident and reflected waves are defined as
A1A2=k1(V1+I1Z1)B1=k2(V2+I2Z2)B2=k1(V1−I1Z1)=k2(V2−I2Z2)
with Z0,i the reference impedance for port i and ki defined as
ki=2ℜ(Z0,i)1ki=α2∣Z0,i∣ℜ(Z0,i)
depending on whether you are using power- or pseudowaves.