# Deembedding and Reflection Coefficient - RF Cafe Forums

The original RF Cafe Forums were shut down in late 2012 due to maintenance issues. Original posts:

RF-Ban
Post subject: Deembedding and reflection coefficient Posted: Wed Jan 11, 2006 10:51 am

Captain

Joined: Sat Feb 26, 2005 5:24 pm
Posts: 16
Location: Lille, FRANCE
Hello,
I am trying to deembed measurements from TDR and i don't see why i can't get the results i want.
I explain my problem:
I have measured through a VNA the reflection coefficients of 3 standards (S0L), and 3 other components. I made a TDR measurement of those components and standards.
From the TDR of the standardsi apply a fft and thanks to the current and voltage i get the measured reflection coefficient of each:
a=(V+ZI)/sqrt(Real(Z));
b=(V-ZI)/sqrt(Real(Z));
S11m=b/a;
Knowing their true reflection coefficients thanks to the VNA, i compute the error vectors:
b=e11;
c=e22;
a=e21-e11*e22;

The problem is that when i use those vectors with TDR of the standards i find back the good s-parameters of the standards, but when i do this with other components i don't find at all.
with :
S11a=(S11m-b)/(a+c.*S11m);

Note : the time span and step, and frequency span and step permits to work one with each other.
Can someone help me ? Thank you

Posted  11/12/2012

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