This article describes some operational changes to two calculators on this site:
Calculate Z from series s21 – enhanced
The previous versions of the calculator required input of the impedance of Port 2 (Zl), and it calculated and reported the Thevenin equivalent source impedance of Port 1 (Zs) from the Zc measurement.
The important data is actually Zs+Zl and this can be directly calculated from Zc, so the calculation has been simplified and entry of Zl is no longer needed. See Derivation of the expression for the unknown impedance in an s21 series through measurement.
The results for Zu are unchanged.
Calculate Z from shunt s21 – enhanced
The previous versions of the calculator required input of the impedance of Port 2 (Zl), and it calculated and reported the Thevenin equivalent source impedance of Port 1 (Zs) from the Zc measurement.
The important data is actually 1/Zs+1/Zl and this can be directly calculated from Zc, so the calculation has been simplified and entry of Zl is no longer needed.
The results for Zu are unchanged.
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.