ETS-Lindgren 5411 GTEM! Test Cell - Manual (Page 57)

GTEM! Manual EUT Manipulator (Optional)
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8.0 GTEM! Manual EUT Manipulator (Optional)
Manual EUT manipulators are designed for use with Model 5407 and Model 5411
to aid with the accurate positioning of the Equipment Under Test (EUT). The
EUT manipulator used in the Gigahertz Transverse Electromagnetic
(GTEM!™) Cell facilitates rapid testing of the EUT using not only the standard
three-position test procedure, but nine, twelve, twelve-plus-four, and other test
procedures that are needed to provide near-field measurements and to
characterize special EUT.
Electromagnetic compatibility (EMC) measurements in the GTEM! require that
the EUT be measured in at least three orthogonal positions. This is necessary to
ensure that enough data is collected to predict or correlate the performance of
the EUT to measurements on an Open Area Test Site (OATS) or in a
semi-anechoic chamber. Whether measuring the EMI emissions or immunity of
EUT, tests must be made in several positions. Positioning the EUT for each
measurement can be done manually, but this can be time consuming and can
require two or three people to reposition the EUT inside the GTEM!. Not only
does changing the EUT position take time, but also supplies of low-permittivity
dielectric materials are needed to support it in each measurement position. The
time to manually position the EUT can be the major part of the total test time
when nine or more positions are needed.
EUT Manipulator Platform Apparatus
The manipulator platform apparatus consists of a cradle with EUT turntable
(top turntable), and a cradle support frame also with turntable (bottom turntable).
Rotation is possible in three axes: the bottom turntable azimuth axis
perpendicular to the floor of the GTEM!, the top turntable azimuth axis
perpendicular to the bottom of the cradle, and the cradle horizontal tilt axis. The
manipulator for the Model 5407 is shown in Manual EUT Manipulator –
Model 5407 on page 60. The manipulator for the Model 5411 is similar in
physical appearance and is sized to fit the recommended test volume of the
larger test cell. The EUT turntable includes holes for anchor points to secure the
EUT during testing. The manipulator is constructed of low-permittivity wood and
non-metallic fasteners to minimize perturbation of the electromagnetic fields.