Agilent Technologies E5071C Manual page 234

Unknown Thru Calibration
Overview
•
Procedure
•
Other topics about Advanced Calibration
Overview
Unknown Thru Cal is the preferred THRU method of calibrating the ENA to
measure a non-insertable device. The major benefits of using a unknown
Thru calibration are:
It is easy to perform.
•
Provides better accuracy than Defined Thru and is usually better than
•
Adapter Removal.
Does not rely on the existing standard definitions that may no longer
•
be accurate.
Causes minimal cable movement if the THRU standard has the same
•
footprint as the DUT. In fact, the DUT can often be treated as the
THRU standard.
The Thru must satisfy the following requirements:
1. Thru must be Reciprocal (with S21 and S12 equal) in nature. It
should have a consistent behavior, independent of the direction from
which it is used.
2. The electrical length of the Thru should be known at an accuracy of
±1 /4 of the wavelength.
3. Unknown Thru is NOT supported during the TRL calibration.
Procedure
To measure the nominal electrical delay of the Unknown Thru standard:
1. With port 1 configured, perform a simple S11 response calibration at
port 1 by using a short circuit
Press
Cal
2. Connect the Unknown Thru standard to port 1 and terminate the
standard with a short circuit.
3. Measure the electrical delay of the Unknown Thru standard
Press
Cal
> Port 1
> Calibrate > Response (Short) > Short
> Port Extensions > Auto Port Extension > Measure SHORT
Measurement
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