Test series 1 – dipole testing – ETS-Lindgren 5411 GTEM! Test Cell User Manual
Page 81
Radiated Emissions Test Performance of GTEM!
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81
T
EST
S
ERIES
1
–
D
IPOLE
T
ESTING
A series of three tuned dipole measurements were accomplished under slightly
different circumstances. The three sets of measurements are as follows:
A set of measurements were performed using only tuned resonant dipoles
covering the frequency range of 500 MHz to 1000 MHz. The measurements were
conducted at three distances, 3, 10, and 30 meters, corresponding to the
three measurement distances common in international commercial EMC
specifications. The measurements were made in a GTEM! and the field strength
calculation was performed at the three measurement distances. The same
dipoles were then transferred to the OATS and comparison measurements
performed. The results of these measurements are shown in the following tables.
Table 1: Tune Resonant Dipole Measurements at 3 Meters
The average difference between the GTEM! and the OATS is –1.97 dB, and the
standard deviation is 1.39 dB.
Frequency
(MHz)
GTEM!
Computed
Field
Strength
(dB uV/m)
OATS
Measured
Field Data
(dB uV/m)
Difference
(dB)
500.0
92.6
93.4
-0.8
600.0
92.3
93.7
-1.4
700.0
91.5
94.2
-2.7
800.0
90.4
92.2
-1.8
900.0
92.3
92.8
-0.5
1000.0
92.2
90.9
+1.4
Table 2: Tune Resonant Dipole Measurements at 10 Meters
The average difference between the GTEM! and the OATS is –1.2 dB, and the
standard deviation is 1.26 dB.
Frequency
(MHz)
GTEM!
Computed Field
Strength
(dB uV/m)
OATS Measured
Field Data
(dB uV/m)
Difference
(dB)
500.0
83.7
83.2
+0.5
600.0
82.1
83.6
-1.5
700.0
81.9
84.4
-2.5
800.0
80.6
82.2
-1.6
900.0
82.5
84.8
-2.3
1000.0
84.1
83.9
+0.2