VNA concepts and features
R&S
®
ZNL/ZNLE
221
User Manual 1178.5966.02 ─ 19
Table 9-6: Calculation of Converted Parallel Transmission Impedances
Traveling Waves
Power Waves
Shunt-thru measurements
The shunt-thru method is used for measuring very low impedances. A typical applica-
tion are measurements on power distribution network (PDN) components, such as
bypass capacitors and DC-DC converters.
The R&S
ZNL/ZNLE uses S
ij
(i≠j) to calculate the DUT impedance using the formula:
DUT
VNA
1
2
9.3.3.2
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
ij
, where i denotes the
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:
Measurement results
