Concepts and features
R&S
®
ZND
189
User Manual 1173.9557.02 ─ 61
VNA
1
3
2
4
DUT
1
2
3
C1
C3
L
p
Balun
Matching circuit
Single-ended
port
Balanced
port
The idea of virtual embedding is to simulate the matching network and avoid using
physical circuitry so that the analyzer ports can be directly connected to the input and
output ports of the DUT. The matching circuit is taken into account numerically. The
analyzer measures the DUT alone but provides the characteristics of the DUT, includ-
ing the desired matching circuit.
This method provides a number of advantages:
●
The measurement uncertainty is not impaired by the tolerances of real test fixtures.
●
There is no need to fabricate test fixtures with integrated matching circuits for each
type of DUT.
●
Calibration can be performed at the DUT's ports. If necessary, (e.g. for compensat-
ing for the effect of a test fixture) it is possible to shift the calibration plane using
length offset parameters.
4.6.2.2
Deembedding a DUT
Deembedding and embedding are inverse operations: A deembedding problem is
given if an arbitrary real network connected to the DUT is to be virtually removed to
obtain the characteristics of the DUT alone. Deembedding is typically used for DUTs
which are not directly accessible because they are inseparably connected to other
components, e.g. for MMICs in a package or connectors soldered to an adapter board.
Offset parameters and de-/embedding
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