Agilent Technologies 4395A - Page 289

Reection
Measurement
(NA)
S-P
arameters
Measurement
S-parameters
S
11
and
S
22
are
no
dierent
from
the
measurements
made
in
the
previous
section.
S
11
is
the
complex
reection
coecient
of
the DUT's
input. S
22
is
the
complex
reection
coecient
of
the
DUT's
output.
In
both cases
,all
unused ports
must be
properly terminated.
To
display
the
trace
on
the
polar
chart,
press
4
Fo
rmat
5
NN
NN
N
N
N
N
N
N
N
N
N
N
N
NN
NN
NN
NN
NN
NN
NN
N
N
N
N
N
N
POLAR CHART
.
The
results
of
a
typical
S
11
measurement is
shown in
Figure 10-11
.Each
point
on
the
polar
trace
corresponds
to
a
particular value
of both
magnitude and
phase.
P
olar
Chart
Shows
Magnitude
and
Phase
Magnitude
The
center
of
the
circle
represents
a
reection
coecient
0
of
0,
that is
,a
perfect match
or no
reected
signal.
The
outermost
circumference
of
the
scale
represents
a0
= 1.00,
or 100
%
reection.
Phase
The
3
o'clock
position
corresponds
to
zero
phase
angle
,
that
is
,
the
reected signal
is at
the same
phase
as
the
incident
signal.
Phase dierences
of
90,
180,
and
270
degrees
correspond
to
the
12,
9,
and
6
o'clock
positions
on
the
polar
display
,
respectively
.
Figure
10-11. S
11
on
Polar
Chart
Data
Readout
Using
the
Marker
Press
4
Ma
rk
er
5
and
use
the knob
to
position
the
marker
at
any
desired
point
on
the
trace
. Then
read the frequency
, magnitude
,
and phase in the upper right hand corner of the display
.Or
,
enter the frequency of interest from the data entry key pad to read the magnitude and
phase
at that point.
To read the marker data in logarithmic
, linear
, real/imaginary
, impedance (R+jX), admittance
(G+jB), or SWR/phase formats
, press
4
Utility
5
NNNN
NNNNNNNNNNNNNNNNNNNNNNNNN
NNNNNNNNNNNNNNNNNN
SMTH/POLAR MENU and select the desired format.
Examples of Applications 10-11