3672 Series Vector Network Analyzer
Contents
In this case, 4 S parameters of the dual-port device include S11, S12, S21 and S22. The S
parameter will be further explained in Fig. 3.2:
a represents the stimulus signal input to the DUT
b represents the reflection and transmission signal (response signal) of the DUT
The S parameter is a plural linear value, and its measuring accuracy depends on the calibration kit
indicators and the applied measurement connection technology, and it is also related to the
non-measurement port (un-activated port).
The ports 1 and 2 are used to measure the dual-port devices to introduce S parameters hereinafter:
Fig. 3.2 Definition of S Parameter
2) Application of S parameter
The S parameter can be used for measurement of the following parameters:
Reflection measurement: SXX (X=1, 2, 3, 4)
Return loss
Standing-wave ratio (SWR)
Reflection coefficient
Impedance
S11, S22, S33, S44
Transmission measurement:
SXY (X=1, 2, 3, 4; Y=1, 2, 3, 4; X≠Y)
Insertion loss
Transmission coefficient
Gain
DUT
S
11
Reflect
a
1
b
1
Incide
S
21
Transmi
b
2
Z
0
Load
a
2
=0
DUT
S22
Reflect
ion
a
2
b
2
S
12
Transmission
b
1
Z
0
Load
a
1
=0
Reverse
Reflection
Incidence
Transmission
Incidence
Reflection
Incidence
Transmission
Incidence