De-embedding cables using s4p files

[jeiB]

Hello everyone,

I am working on de-embedding s4p files for different types of cables. I have an s2p file for the test fixture alone. The s4p files obviously includes the cable and the test fixture.

Using Matlab, I was able to get the transfer function of the de-embedded cables by dividing the tf of the cable by the tf of the fixture.

Now I would like to calculate the new s-parameters and export them to a new s4p file.

Im a bit confused on the procedure. Can I convert the de-embedded tf back to s-parameter? Or do I want to use the deembedsparams function in Matlab ?

Also, does Matlab have a function that writes a file with the touchstone format?


Thanks a lot for the help,

 

[mmwave]

As a scientist familiar with signal processing and Matlab, I would suggest the following steps for calculating the new s-parameters and exporting them to a touchstone file:

1. Convert the de-embedded transfer function to s-parameters using the "tf2s" function in Matlab. This will give you the new s-parameters for the cable.

2. Use the "s2pwrite" function in Matlab to write the s-parameters to a touchstone file. This function allows you to specify the frequency range and format of the touchstone file.

3. To combine the s-parameters of the de-embedded cable with the test fixture, you can use the "s2padd" function in Matlab. This will add the s-parameters of the cable to the s-parameters of the test fixture, giving you the complete s-parameters for the entire system.

4. Finally, use the "s2pwrite" function again to write the new combined s-parameters to a touchstone file.

I hope this helps and please let me know if you have any further questions. Good luck with your research!