# Deembedding and reflection coefficient - RF Cafe Forums

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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