Agilent Technologies E5070B, User Manual

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Chapter 4 153
Calibration
Unknown Thru Calibration
4. Cal
ibra
tion
Unknown Thru Calibration
Unknown Thru Calibration is the preferred THRU methord of calibrating the
E5070B/E5071B 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.
• Dose not relies on 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
wavelength.
NOTE Unknown Thru is NOT supported during a TRL calibration.
Procedure
The s-parameter of a thru can be determined when the following data is available:
1. Open, Short and Load measurement.
2. Actual, values derived from the calibration kit definitions.
To perform the Unknown Thru Calibration, follow the given procedure.
Procedure to select and define the name of the calibration kit
Step 1. Press .
Step 2. Press
CalKit
.
Step 3. Select desired calibration kit. (e.g. 85033D or user kit)
Step 4. Press
Modify CalKIt
.
Step 5. Press
Define STDs
.
Step 6. Press
No Name
.
Step 7. Press
Label
.
Step 8. Type a name for unknown thru calibration standard. (e.g. Unknown Thru)
NOTE By changing the label to a different name (e.g. Unknown Thru1), the “No Name” standard
will adopt the specified new name.