Specifications

ETSI
Final draft ETSI EN 300 328 V1.8.1 (2012
-
04)
67
Figure B.3: A typical Fully Anechoic Room
The chamber shielding and radio absorbing material work together to provide a controlled environment for testing
purposes. This type of test chamber attempts to simulate free space conditions.
The shielding provides a test space, with reduced levels of interference from ambient signals and other outside effects,
whilst the radio absorbing material minimizes unwanted reflections from the walls and ceiling which can influence the
measurements. The shielding should be sufficient to eliminate interference from the external environment that would
mask any signals that have to be measured.
A turntable is capable of rotation through 360° in the horizontal plane and it is used to support the UUT at a suitable height
(e.g. 1 m) above the ground plane.
The measurement distance and minimum chamber dimensions can be found in clause B.1.4. The distance used in actual
measurements shall be recorded with the test results.
Further information on Fully Anechoic Rooms can be found in TR 102 273-2 [i.12].
B.1.4 Measurement Distance
The measurement distance should be chosen in order to measure the UUT at far-field conditions. The minimum
measurement distance between the equipment and the measurement antenna should be
or r
m >>
λ
2
D
, whichever is
the greater.
= wavelength in m
r
m
= minimum measurement distance between UUT and measurement antenna in m
D = largest dimension of physical aperture of the largest antenna in the measurement setup, in m