Agilent Technologies 4395A - Page 422

Calibration
for
Network
Measurement
T
able A
-2. Standard
Denitions
NO
.
Standard
Type
C0
2
10
0
15
F
C1
2
10
0
27
F/Hz
C2
2
10
0
36
F/Hz
2
Oset
Delay
ps
Oset
Loss
M/s
Oset
Z
0

Standard
Label
1
2
3
4
5
6
7
8
Each
standard
must be
identied
as
one
of
ve
\types":
OPEN,
SHORT
,
LO
AD
,
DELA
Y/THRU
,
or
arbitrary
impedance
.
Standard
Types
OPEN
OPENs
assigned
a terminal
impedance of
innite
ohms
,
but
delay
and
loss
osets
may
still
be
added.
F
or information
of
the
delay
and
loss
osets
,
see
the
\Oset
and
Delay"
paragraph.
As
a
reection
standard,
an
OPEN
oers
the
advantage
of
broadband
frequency
coverage
.
However
,
an
OPEN
rarely
has
perfect
reection
characteristics
because
fringing
(capacitance)
eects
cause
phase
shift
that
varies
with
frequency
.
This
can
be
observed in
measuring
an
OPEN
termination
after
calibration,
when
an
arc
in
the
lower
right circumference
of
the
Smith
chart
indicates
capacitive
reactance
.
These
eects
are
impossible
to
eliminate
,
but
the
calibration
kit
models
include
the
OPEN
termination
capacitance
at
all
frequencies
for
compatible
calibration
kits
.
The
capacitance
model
is
a
second
order
polynomial
(squared
term),
as
a
function
of
frequency
,
where
the
polynomial
coecients
are
user-denable
.
The
capacitance
model
equation
is:
C =
C
0
+ C
1
2 F
+ C
2
2 F
2
where F
is the
measurement frequency
.
SHORT
SHORTs are assigned a terminal impedance of 0 , but delay and loss osets may still be
added.
LOAD
LOADs are assigned a terminal impedance equal to the system characteristic impedance Z
0
,
but delay and loss osets may still be added.
If the LO
AD impedance is not Z
0
, use the
arbitrary impedance standard denition.
DELAY/THRU
DELAY/THRUs are assigned a transmission line of specied length, for calibrating
transmission measurements.
ARBITARY IMPEDANCE
A-46 Basic Measurement Theory