VNA Measurements 4-6 Waveguide Considerations
Vector Network Analyzer MG PN: 10580-00289 Rev. K 4-15
Note
When measuring reflection parameters (such as S
11
in the Figure 4-12 example),
the distance domain measurement is adjusted so that the peak of the signal is at
the end of the cable or waveguide (a length of 15 cm in the example). This is called
a One-Way representation of the measurement. The signal itself travels round-trip
to the end of the cable and then back to the port.
If the VNA Master does not adjust for the round-trip condition, then the peak of the
signal will be at a distance that is twice the length of the cable (in which case, the
measurement would have been called Round-Trip).
In the time domain, you can choose to set the reflection measurement to be either
One-Way or Round-Trip. When set to One-Way (which is the default setting), the
VNA Master compensates for the round trip reflection measurement as it does in
the Distance Domain. When set to Round-Trip, the VNA Master does not
compensate, and the peak of the signal in the time domain therefore represents
the time that is taken for the signal to reach the end of the cable and reflect back to
the port (1.3 ns in the Figure 4-12 example).
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