VNA concepts and features
R&S
®
ZNL/ZNLE
265
User Manual 1178.5966.02 ─ 19
Accuracy considerations
To ensure an accurate calibration, please observe the following items:
●
Unused ports of the calibration unit must be terminated with a 50
Ω match.
●
No adapters must be inserted between the calibration unit and the test ports of the
analyzer.
●
Allow for a sufficient warm-up time before starting the calibration. Refer to the
specifications of the calibration unit for details.
●
To ensure best accuracy, the analyzer automatically reduces the source power to
-10
dBm. If the test setup contains a large attenuation, deactivate "Auto Power Set-
ting for Cal Unit" in the "Calibration" tab of the VNA Setup dialog. Ensure an input
power of -10
dBm at the ports of the calibration unit (please also refer to the speci-
fications of the calibration unit).
Maximum RF input power
The maximum RF input power of the calibration unit is beyond the RF output power
range of the analyzer, so there is no risk of damage if the device is directly connected
to the test ports. If you use an external power amplifier, make sure that the maximum
RF input power of the calibration unit quoted in the data sheet is never exceeded.
The available calibration types depend on the number of ports to be calibrated. For a
single calibrated port, the reflection calibration types are available ("Refl Norm Open",
"Refl Norm Short", "Refl OSM").
If 2 ports should be calibrated, the analyzer provides the following additional calibration
types:
●
A single full 2-port (TOSM or UOSM) calibration.
A single full 2-port (TOSM or UOSM) calibration.
●
Two full one-port calibrations for the two calibrated ports.
●
A one path two port calibration. The node port is the source port for the one path
two port calibration (fully calibrated port).
●
A transmission normalization (bidirectional, forward or reverse). "Forward" trans-
mission normalization means that the signal direction is from port 1 to port 2.
9.5.5.3
Characterization of calibration units
Each calibration unit is delivered with factory characterization data which ensure an
accurate calibration for all standard applications. For specific modifications of the test
setup, e.g. the connection of additional adapters to a calibration unit, a modified set of
characterization data (suitable for the cal unit with adapters) may be desirable. The
R&S
ZNL/ZNLE provides a characterization wizard which you can use to generate your
own characterization data sets for (modified) R&S cal units. The characterization data
can be stored in the cal unit and used for automatic calibration whenever needed.
Calibration