Agilent Technologies 4395A - Page 432

Calibration
for
Network
Measurement
Reection Tracking,
E
RF
Reverse
Directivity,
E
DR
Isolation, E
XR
Source Match,
E
SR
Load Match,
E
LR
Transmission
Tracking,
E
TR
Reection
Tracking,
E
RR
The
87511A,
B
S-parameter
T
est
sets
can
measure
both
the
forward
and
reverse characteristics
of
the
test
device
without
the
need
to
manually
remove
and
physically
reverse
it. With
these
test
sets
,
the
full
two-port
error
model
illustrated
in
Figure
A
-40
eectively removes
both the
forward
and
reverse
error
terms
for
transmission
and
reection
measurements
.
The
87512A,
B
Transmission/Reection
T
est
kits
cannot
switch
between
forward
and
reverse
directions
,
so
the
reverse
error
terms
cannot
be
automatically
measured.
Therefore,
with
the
one-path
two-port
calibration,
the
forward
error
terms
are
duplicated
and
used for
both
forward
and
reverse
measurements
by
manually
reversing
the
test
device
.
Figure A
-40. Full Two-P
ort Error Model
The following equations show the
full two-port error model equations for all four S-parameters
of a two-port device. Note that the mathematics for this comprehensive model use all forward
and reverse error terms and measured values. Thus, to perform full error correction for any
one parameter, all four S-parameters must be measured.
A-56 Basic Measurement Theory