Almost. S21 is sq_root of the power transfer. Power transfer is idependent of impedance. S21*sqroot(Z0) would be more representative of the voltage transfer function.

In pages 24, 23 I find a different expression to obtain the voltage transfer in terms of the S parameters and the load reflection coefficient. Are both ways of determining the transfer function correct?

Is it correct to assume that measuring with the VNA the source and load impedances are equal to the reference impedance (Zl=Zs=Zo=50 Ohm)? In this case, the expression in page 24 of the document would reduce to Av=S21/(1+S11). Is it correct?

http://cp.literature.agilent.com/litweb ... 2-1087.pdf

In pages 24, 23 I find a different expression to obtain the voltage transfer in terms of the S parameters and the load reflection coefficient. Are both ways of determining the transfer function correct?

Is it correct to assume that measuring with the VNA the source and load impedances are equal to the reference impedance (Zl=Zs=Zo=50 Ohm)?

In this case, the expression in page 24 of the document would reduce to Av=S21/(1+S11). Is it correct?

Thank you very much