Specifications

ETSI
Final draft ETSI EN 300 328 V1.8.1 (2012
-
04)
65
Figure B.1: A typical Open Area Test Site
The ground plane creates a wanted reflection path, such that the signal received by the receiving antenna is the sum of
the signals received from the direct and reflected transmission paths. The phasing of these two signals creates a unique
received level for each height of the transmitting antenna (or UUT) and the receiving antenna above the ground plane.
The antenna mast provides a variable height facility (from 1 m to 4 m) so that the position of the measurement antenna
can be optimized for maximum coupled signal between antennas or between a UUT and the measurement antenna.
A turntable is capable of rotation through 360° in the horizontal plane and it is used to support the test sample (UUT) at a
specified height, usually 1,5 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 Open Area Test Sites can be found in TR 102 273-4 [i.14].
B.1.2 Semi Anechoic Room
A Semi Anechoic Room is - or anechoic chamber with a conductive ground plane - is an enclosure, usually shielded,
whose internal walls and ceiling are covered with radio absorbing material. The floor, which is metallic, is not covered
by absorbing material and forms the ground plane. The chamber usually contains an antenna mast at one end and a
turntable at the other end. A typical anechoic chamber with a conductive ground plane is shown in figure B.2.
This type of test chamber attempts to simulate an ideal Open Area Test Site, whose primary characteristic is a perfectly
conducting ground plane of infinite extent.