HP 8753D - Page 334

Electrical
Oset
Some
standards have
reference
planes
that
are
electrically
oset
from
the
mating
plane
of
the
test
port. These
devices
will
show
a
phase
shift
with
respect
to
frequency
.
Table
6-3 shows
which
reference devices
exhibit
an
electrical
oset
phase
shift.
The
amount
of
phase
shift
can
be
calculated with
the
formula:

=
(360
x
f
x
l)/c
where:
f
=
frequency
l
=
electrical
length
of
the
oset
c
=
speed
of
light
(3
x
10
8
meters/second)
Fringe
Capacitance
All
open
circuit
terminations
exhibit
a
phase
shift
over
frequency
due
to
fringe capacitance
.
Oset
open
circuits
have
increased
phase
shift
because
the
oset
acts
as
a small
length of
transmission
line
.
Refer
to
T
able
6-3
.
T
able
6-3.
Calibration
Standard
Types
and
Expected
Phase
Shift
T
est
P
ort
Connector
Type
Standard
Type
Expected
Phase
Shift
7-mm Short 180

Type-N
male
3.5-mm
male
Oset
Short
180

+
(360
2
f
2
l
)
c
3.5-mm
female
2.4-mm
male
2.4-mm
female
Type-N
female
75
Type-N female
7-mm Open 0

+

capacitance
Type
N-male
3.5-mm
male
Oset
Open
0

+ 
capacitance
+
(360
2
f
2
l
)
c
3.5-mm female
2.4-mm
male
2.4-mm female
Type N-female
Open
0

+ 
capacitance
+
(360 2 f 2 l )
c
75 Type-N female
Application and Operation Concepts 6-67