How to change 3 ports s-parameter to Reflection coefficient

Dear,
I have a s-parameter of a 3-ports network ,can I know the reflection coefficient of Port11?
BR,
Thank you!

For port 1

it is S11

For port 2

it is S22

and for port 3

it is S33 !

Or did I wrongfully understand the question ?

you can do the S11 format converter using ADS easily.

Thank you ,your idea is helpful!
And if anyone have the formulations ,pls show it .thank you~

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Thank you ,your idea is helpful!
And if anyone have the formulations ,pls show it .thank you~

S11 is the reflection coefficient (gamma).

Reflection coeff is defined here: http://en.wikipedia.org/wiki/Reflection_coefficient

We know that gamma = ratio of V-/V+ (or E-/E+, if you use E for voltage/electromotive force). Sxx (like S11) is also the voltage ratio of V-/V+ for the device under test, if you understand how S-parameters are determined, and what they represent.

I think only if all ports match ,gamma=Sxx

The reflection coefficient is also a function of the loads of other ports, not only the s parameter itself. For example, just connect two ports of different value of impedance with a 50 ohm line. S11 of this line is 0, however, the gamma looking from one port is not 0 in this case.

Yes. But that's generally assumed when you are measuring return loss (standard practice).