R&S ZVB - Measured Quantities; S-Parameters

R&S
®
ZVA / R&S
®
ZVB / R&S
®
ZVT System Overview
Measured Quantities
Operating Manual 1145.1084.12 – 30 43
Complex dimensionless
quantities:
S-parameters and ratios
Complex quantities with dimensions:
Wave quantities, Z-parameters, Y-parameters,
impedances, admittances
Real quantities:
Stability Factors, DC
Input 1/2, PAE
Real
Imag
–
Unwrapped
Phase
–
Smith
(reflection coefficients S
ii
)
–
–
Polar
–
–
Inverted Smith
(reflection coefficients S
ii
)
–
–
SWR
(reflection coefficients S
ii
)
–
–
Delay
(transmission coefficients
S
ij
)
–
–
The default formats are activated automatically when the measured quantity is changed.
Measured Quantities
This section gives an overview of the measurement results of the network analyzer and the meaning of
the different measured quantities. All quantities can be selected in the Trace – Meas. submenu.
The definitions in this and the following sections apply to general n-port DUTs. An analyzer with a
smaller number of test ports provides a subset of the n-port quantities.
S-Parameters
S-parameters are the basic measured quantities of a network analyzer. They describe how the DUT
modifies a signal that is transmitted or reflected in forward or reverse direction. For a 2-port measurement
the signal flow is as follows.
Extensions to the signal flow
The figure above is sufficient for the definition of S-parameters but does not necessarily show the
complete signal flow. In fact, if the source and load ports are not ideally matched, part of the transmitted
waves are reflected off the receiver ports so that an additional a
2
contribution occurs in forward
measurements, and an a
1
contribution occurs in reverse measurements.
The 7-term calibration types Txx take these additional contributions into account.
The scattering matrix links the incident waves a
1
, a
2
to the outgoing waves b
1
, b
2
according to the following