Specifications

7-4 MEASUREMENT
CALIBRATION—SLIDING
TERMINATION
Sliding terminations (loads) are the traditional Z
0
calibration-
reference devices for Vector Network Measurement System
calibration. When correctly used and perfectly aligned, they can be
more accurate than precision fixed loads. However, sliding
terminations have a 2 GHz (4 GHz for V-Connector sliding loads)
low-frequency limit and must be used with a fixed load for full
frequency-range coverage
.
Sliding terminations consist of a connector, a long section of precision
transmission line, and a microwave load that is movable within the
transmission line. Pin depth—the relationship between the interface
positions of the outer and center conductors—is the most critical
parameter that you can control in a sliding termination. An example of
its criticality is that an incorrect pin depth of 0.001 inch can cause a
reflection return loss of 44 dB. Since you are usually calibrating to
accurately measure a greater than 40 dB return loss, correct pin depth
is essential.
Since setting an accurate pin depth is so important, this discussion
centers on describing how to set the pin depth for male and female
sliding terminations. Calibration with the sliding termination is
essentially the same as described below for the broadband load.
The procedure below uses the Model 3652 Calibration Kit and its
17KF50 and 17K50 Sliding Terminations. Calibration is similar for
the Model 3650 SMA/3.5mm, Model 3651 GPC-7 and Model 3654B
V-connector kits. For the 3651, the procedure is simpler because the
GPC-7 connector is sexless, there is only one sliding termination.
Procedure
Step 1. Remove the Pin Depth Gauge from the kit, place it
on the bench top.
NOTE
The meter is convertible between male and
female. The following procedure describes
the zeroing process for the female fitting.
The procedure for the male fitting begins
with step 16.
MEASUREMENT MEASUREMENT CALIBRATION
CALIBRATION SLIDING -TERMINATION
MS462XX OM 7-13