Typical e-field frequency response – model 5407, Electric field uniformity, Typical electric field uniformity – model 5407 – ETS-Lindgren 5411 GTEM! Test Cell User Manual
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Measured GTEM! Performance
T
YPICAL
E-F
IELD
F
REQUENCY
R
ESPONSE
–
M
ODEL
5407
Following is a typical Model 5407 vertical electric field frequency response
normalized to 10 W constant forward power at a center point where the septum
height is 80 cm (40 cm above the floor). At other locations electric field frequency
response can vary by several dB.
E
LECTRIC
F
IELD
U
NIFORMITY
The electric field uniformity of a GTEM! can be defined as the maximum
difference in dB between measured electric field at various spatial locations on a
plane perpendicular to the direction of propagation. According to the
IEC 61000-4-20 standard, the uniform area to be measured and the minimum
number of points depend on the size of the GTEM!. At each frequency, the
reference location can be arbitrarily chosen; for example the center or bottom
corner point of the calibration plane. After performing the plane calibration in the
empty GTEM!, the Equipment Under Test (EUT) is inserted with the front face
coincident with the calibration plane.
T
YPICAL
E
LECTRIC
F
IELD
U
NIFORMITY
–
M
ODEL
5407
The electric field uniformity of a Model 5407 as measured according to
EN 61000-4-20 is shown in the following. Five spatial points were measured in a
633 mm x 250 mm vertical/transverse plane centered at an 80-cm septum height.
The standard allows 25% of the points to be omitted at each frequency; at least
four of the five points fulfill the –0, +6 dB criteria as required.