"camelot" wrote in message
ups.com...
Thank you for your comments,
I'm doing some calculations and simulations in order to verify if I
can bypass representation problem of s-parameters in other ways rather
than the Thevenin one.
There is one thing I'd like to submit to your attention, the known
formula
S11=(Zin-Z0)/(Zin+Z0),
where Z0 is the port impedance and Zin the load, does not works if you
consider Z0 not pure real (usually 50 ohm) but composed by a real and
an imaginary part i.e. Z0 = a+jb.
Are there other known formulas for S11 for Z0 real+imaginary?

Actually, characteristic impedance Z0 is assumed to be 50 Ohm, 300 Ohm or 75
Ohm (etc.), based on the type of transmission line, under the assumption
that the line is "lossless", thus in theory only it only considers the
complex components.

For a lossless line, Z0 = sqrt(L/C)

In reality, the resistance (conductance) must be considered, whe

Z0 = sqrt((r+jwl)/(G+jwC))