VNA Concepts and Features
R&S
®
ZNL/ZNLE
247
User Manual 1178.5966.02 ─ 07
If isolation is measured, the corrected transmission coefficient of the DUT is calculated
as:
(Transmission coefficient DUT – Isolation) / (Transmission coefficient Through – Isola-
tion)
There is no dedicated physical standard for isolation measurement; it is recommended
to terminate the test ports suitably (e.g. with 50 Ω loads).
8.5.2
Calibration Standards and Calibration Kits
A calibration kit is a set of physical calibration standards for a particular connector type.
The magnitude and phase response of the calibration standards (i.e. their S-parame-
ters) must be known or predictable within a given frequency range.
The standards are grouped into several types (Open, Through, Match,...) correspond-
ing to the different input quantities for the analyzer's error models. The standard type
also determines the equivalent circuit model used to describe its properties. The circuit
model depends on several parameters that are stored in the cal kit file associated with
the calibration kit.
As an alternative to using circuit models, it is possible to describe the standards with S-
parameter tables stored in a file.
The analyzer provides many predefined cal kits but can also import cal kit files and cre-
ate kits:
●
A selection of predefined kits is available for all connector types. The parameters of
these kits are displayed in the "View / Modify Cal Kit Standards" dialog, however, it
is not possible to change or delete the kits.
●
Imported and user-defined kits can be changed in the "Calibration Kits" dialog and
its various subdialogs.
Calibration kits and connector types are global resources; the parameters are stored
independently and are available irrespective of the current channel setup.
8.5.2.1
Calibration Standard Types
The following table gives an overview of the different standards and their circuit models
(offset and load models).
Table 8-5: Calibration standard types
Standard Type
Characteristics
Ideal Standard
Offset Model Load Model
Open
Open circuit (one-port)
∞
Ω
☑
☑
Short
Short circuit (one-port)
0 Ω
☑
☑
Offset short
Short circuit with added electrical length offset, for
waveguide calibration (one-port)
0 Ω
☑
☑
Match
Matched broadband termination (one-port)
Z
0
(characteristic
impedance of the
connector type)
☑
☑
Calibration
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Allice Messtechnik GmbH
