Calculate Z from series S21 - enhanced

This calculator calculates Z from series S21 and related calibration measurements.

Inputs:

	Real /magnitude	Imaginary / angle
Zc
S21c
S21u

Results:
Zc (Ω)
Zs+Zl (Ω)
Zu (Ω)
Yu (Ω)

The calculator does not do a lot of error checking, if you enter nonsense, it will probably produce nonsense.

Inputs are assumed wrt 50+j0 (Ω).

A series impedance Zc is used to find the equivalent source impedances of Port 1 plus Port 2 (Zs+Zl) for improved accuracy. Zc is measured using a s11 reflection measurement.

s21c is an s21 measurement with Zc in series from Port 1 to Port 2.

s21u is an s21 measurement with Zu (the unknown) in series from Port 1 to Port 2.

Links / references

Agilent. Feb 2009. Impedance Measurement 5989-9887EN.
Agilent. Jul 2001. Advanced impedance measurement capability of the RF I-V method compared to the network analysis method 5988-0728EN.

Changes

Version	Date	Description
1.01	13/02/2021	Initial.
1.02	28/05/24	Revised to use Zs+Zl.
1.03
1.04
1.05