Rohde & Schwarz R&S ZNA Series - 4.3.6.1 Balanced port configurations

Concepts and features
R&S
®
ZNA
162User Manual 1178.6462.02 ─ 29
VNA
1 2
Physical VNA ports
Common
mode
Differential
mode
Physical
transformer
(balun)
DUT
VNA
1 2
DUT
Balanced port
Internal balance-
unbalance
conversion
Logical
VNA ports
Unbalance-balance conversion avoids the disadvantages of real transformers:
●
There is no need to fabricate test fixtures with integrated baluns for each type of
DUT.
●
The measurement is not impaired by the non-ideal characteristics of the balun (e.g.
error tolerances, limited frequency range).
●
Calibration can be performed at the DUT's ports. If necessary (e.g. to compensate
for the effect of a test fixture), it is possible to shift the calibration plane using length
offset parameters.
●
Differential and common mode parameters can be evaluated with a single test
setup.
4.3.6.1 Balanced port configurations
Defining a balanced logical port requires two physical ports.
The physical ports (on the VNA and connected External switch matrices) are equiva-
lent and can be freely combined to balanced (logical) ports. Moreover, it is possible to
assign arbitrary, independent reference impedance values to each unbalanced port
and to the differential and common mode of each logical port.
Measurement results