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Chapter 4 121
Calibration
Full 3-Port Calibration
4. Cal
ibra
tion
Full 3-Port Calibration
In full 3-port calibration, calibration data are measured by connecting an OPEN standard, a
SHORT standard, or a LOAD standard to three desired test ports (or a THRU standard
between three ports). This calibration effectively eliminates the directivity error, crosstalk,
source match error, load match error, frequency response reflection tracking error, and
frequency response transmission tracking error from the test setup in a transmission or
reflection test using those ports (Figure 4-17). As in full 2-port calibration, this calibration
method also makes it possible to perform measurements with the highest possible
accuracy. There are unique error terms for directivity, source match, and reflection tracking
for each stimulus test port (3
×
3 ports = 9). As for isolation, load match, and transmission
tracking errors, there are unique terms for each combination between a stimulus port and a
response port (3
×
6 combinations = 18). Therefore, in total, 27 error terms are involved in
a full 3-port calibration.
Figure 4-17 Full 3-port error model (Options 313, 314, 413, and 414)