Electrical Offset - HP 8753E User Manual

Electrical Offset

Some standards have reference planes that are electrically offset from the mating plane of the
test port. These devices will show a phase shift with respect to frequency. 'lhble 6-4 shows
which reference devices exhibit an electrical offset phase shift. The amount of phase shift can
be calculated with the formula:
f = frequency
1 = electrical length of the offset
c = speed of light (3 x 10s meters/second)
Fringe Capacitance
All open circuit terminations exhibit a phase shift over frequency due to fringe capacitance.
Offset open circuits have increased phase shift because the offset acts as a small length of
transmission line. Refer to lhble 6-4.
Port
Connector Type
Type-N male
Type-N female
Type N-female
763 Type-N female
Application and Operation Concepts
Offset Open
Expected Phase Shift
(360 x f x I)