System Overview
R&S
®
ZVA
84
Quick Start Guide 1145.1090.62 ─ 10
●
d: Differential mode (for balanced ports)
●
c: Common mode (for balanced ports)
The notation of a general S-parameter is S
<mout><min><out><in>
, where <mout> and <min>
denote the output and input port modes, <out> and <in> denote the output and input port
numbers.
Meaning of 2-port mixed mode S-parameters
The mixed mode 2-port S-parameters can be interpreted as follows:
●
S
<mout><min>11
is the mixed mode input reflection coefficient, defined as the ratio of the
wave quantities b
1
(mode mout) to a
1
(mode min), measured at PORT 1 (forward
measurement with matched output and a
2
= 0).
●
S
<mout><min>21
is the mixed mode forward transmission coefficient, defined as the ratio
of the wave quantities b
2
(mode mout) to a
1
(mode min) (forward measurement with
matched output and a
2
= 0).
●
S
<mout><min>12
is the mixed mode reverse transmission coefficient, defined as the ratio
of the wave quantities b
1
(mode mout) (reverse measurement with matched input,
b
1
' in the figure above and a
1
= 0) to a
2
(mode min).
●
S
<mout><min>22
is the mixed mode output reflection coefficient, defined as the ratio of
the wave quantities b
2
(mode mout) (reverse measurement with matched input, b
2
'
in the figure above and a
1
= 0) to a
2
(mode min), measured at PORT 2.
If <mout> is different from <min>, the S-parameters are called mode conversion factors.
3.3.2.14
Mixed Mode Parameters for Different Test Setups
Which types of mixed mode parameter are available depends on the measured device
and the port configuration of the analyzer. The following examples of mixed more param-
eters can all be obtained with a 4-port analyzer.
1. DUT with only single-ended ports: No balanced port definition necessary, the ana-
lyzer provides single-ended multiport parameters.
2. DUT with one balanced port: Only reflection and mode conversion measurements
with differential and common mode parameters.
Measured Quantities
