R&S ZNB Series User Manual page 133

®
R&S ZNB/ZNBT
4.3.3.2 Z-parameters
The Z-parameters describe the impedances of a DUT with open output ports (impe-
dance = 0). The analyzer provides the full set of Z-parameters including the transfer
impedances (i.e. the complete nxn Z-matrix for an n port DUT).
This means that Z-parameters can be used as an alternative to S-parameters (or Y-
parameters) to characterize a linear n-port network completely.
2-port Z-parameters
In analogy to S-parameters, Z-parameters are expressed as Z
measured and j the stimulated port.
The Z-parameters for a two-port are based on a circuit model that can be expressed
with two linear equations:

V
1

V
2
Meaning of Z-parameters
The four 2-port Z-parameters can be interpreted as follows:
●
Z
measured at port 1 (forward measurement with open output, I
●
Z
current I
●
Z
current I
User Manual 1173.9163.02 ─ 62
VNA
1 2
DUT

Z I Z I
11 1 12 2

Z I Z I
21 1 22 2
is the input impedance, defined as the ratio of the voltage V
11
is the forward transfer impedance, defined as the ratio of the voltage V
21
(forward measurement with open output, I
1
is the reverse transfer impedance, defined as the ratio of the voltage V
12
(reverse measurement with open input, I
2
Concepts and features
Measurement results
, where i denotes the
ij
to the current I
1
= 0).
2
= 0).
2
= 0).
1
,
1
to the
2
to the
1
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