Specifying individual port impedances in RF toolbox.

I'm trying to convert the S-parameters of a measurement to a different port impedance on port1, while keeping port2 at 50Ω. From everything I found so far the extract and s2s functions only take a scalar as port impedance and hence would convert port2 as well.

Short of writing code to implement the equations of renomalization myself, how do I do this in the RF toolbox

[Riccardo Micci]

I have the same issue, so far i could not find any way to do it.

Answer 1

[Abhinav Aravindan]

The “s2s” function for converting S-parameters to match different port impedances has been updated in MATLAB R2023a to specify a different reference impedance for each port in the network.

https://www.mathworks.com/help/rf/ref/s2s.html#:~:text=Specify%20a%20different%20reference%20impedance%20for%20each%20port%20in%20the%20network%20by%20setting%20the%20z0%20argument%20to%20a%20vector.

The “s2s” function can be implemented as follows for converting the S-parameters to a different port impedance on Port 1, while keeping Port 2 at 50Ω, considering initial Port impedances as 50Ω

% Sample S-Parameters 
s_11 = 0.61*exp(1i*165/180*pi); 
s_21 = 3.72*exp(1i*59/180*pi); 
s_12 = 0.05*exp(1i*42/180*pi); 
s_22 = 0.45*exp(1i*(-48/180)*pi); 
s_params = [s_11 s_12; s_21 s_22]; 

% Initial Impedance ([Port1 Port2]) 
z0 = [50 50]; 

% New Impedance ([Port1 Port2]) 
z0_new = [40 50]; 

% Modified S-Parameters 
s_params_new = s2s(s_params, z0, z0_new); 

Output: