#### seackone

##### Junior Member level 1

I got a question about simple smith chart basic:

Szenario: I got the s-parameters of a network at only one frequency. The s-parameters are splitted into real -and imaginary part and measured with a network analyzer (50 Ohm termination). The parameter of interest is only S11.

I want to plot S11 in a smith chart, so i have to calculate the impedance:

Z = (1+(real(S11)+j*imag(S11))) / (1-(real(S11)+j*imag(S11)))

An other parameter could be the absolute reflection coefficient (and the angle..):

|r| = sqrt(real(S11)^2 + imag(S11)^2)

With Z, is possible to plot the smith chart with a reference to 50 ohm. But what is, if I change my reference to 60 ohm for example? Are there any changes of the position and reflection coefficient of my measured network in the smith chart or is it just a change if Im looking at my denormalized impedance:

impedance = Z0 * Z

If im looking at the last formular, there is no change in position.. or should the formula be more like:

impedance = Z0_NWA * Z / Z0 = 50*Z / 60

than there is a change in position or the value of the reflection coefficient.