Agilent Technologies 8719ES User Manual page 416

Operating Concepts
Measurement Calibration
Figure 7-32 Open Circuit Termination
This completes the calibration procedure for one port devices.
Device Measurement
Now the unknown is measured to obtain a value for the measured response, S , at each
11M
frequency. Refer to Figure 7-33.
Figure 7-33 Measured S
11
This is the one-port error model equation solved for S . Since the three errors and S
11A 11M
are now known for each test frequency, S can be computed as follows:
11A
( )
S – E
11M DF
S = ---------------------------------------------------------------- -
11A
( )
+ E
E S – E
RF
SF 11M DF
For reflection measurements on two-port devices, the same technique can be applied, but
the test device output port must be terminated in the system characteristic impedance.
This termination should have as low a reflection coefficient as the load used to determine
directivity. The additional reflection error caused by an improper termination at the test
device's output port is not incorporated into the one-port error model.
7-46