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Global EMC have great experience in all types of anechoic chamber manufacture. Careful planning, precise installation and proven fitting systems allow Global EMC to maximise the anechoic materials to ‘best effect’ for optimum anechoic performance. Our chamber experience allows us to accuately forecast the measurement certainty in the following chamber types:
• Partial lining or progressive coverage
• Fully anechoic microwave chambers
• Compact EMC test chambers (semi & fully anechoic)
• Compliant test chambers
Global EMC always use independeant test companies so as to have unbiased calibration test results. Each set of test results are analysed and recorded so as to be sure our forecast is in line with the final test results. Where guarantees of performance are given by Global EMC we always achieve compliance to those guarantees without fail.
3 METRE COMPLIANT CHAMBERS
A 3m ‘compliant’
chamber is compliant to ANSI C 63.4/
EN50147-2 (emissions) and IEC/EN61000.4.3 (immunity) standards.
The standard size of a 3M compliant chamber is around 9m long x 6m wide
and 5.5m high.
This type of chamber has all wall and ceiling covered with ferrite tile
with some hybrid areas so as to have high frequency performance.
A compliant 3m test
chamber would have a reflective floor when emission testing and would have
floor absorbers when immunity testing.
Standard equipment requirement of a 3m test chamber would be turntable
to rotate the equipment under test and a 1 to 4m high antenna mast to
amortise the ground reflections (if required, Global EMC provide these
as a total system)
3 METRE
COMPLIANT
CHAMBERS ARE
VERY HIGH IN
TERMS OF BOTH
SHIELDING AND
MEASUREMENT
ACCURACY
HAVE MANY YEARS
EXPERIENCE
IN COMPACT
CHAMBERS
WITH NEW
LEVELS OF
MEASUREMENT
ACCURACY
AND QUALITY
FINISH
COMPACT ANECHOIC
CHAMBERS
Compact
anechoic chambers are for 3 metre separation between the equipment under test
(EUT) and the antenna.Compact chambers normally have a size of 7m long x 3.5
or 4m wide & 3m high but can vary slightly.
There are two basic
of anechoic lining designs:
Semi anechoic - where the walls
and ceiling have anechoic absorbers but the floor is remains reflective (for
emissions tests). This type of lining correlates to open area test site (OATS).
During the emissions test the antenna should be swept so as to amortise the
ground plane reflections (as on OATS) For
immunity testing floor absorbers between the EUT and antenna are needed.
Fully
anechoic - Where all internal surfaces are covered with anechoic
absorbers. This type of anechoic lining correlates to free space and the receive
antenna remains at a fixed height.
Our all fully ferrite + hybrid chambers have reached new levels of measurement
accuracy (see graphs) combined with quality chamber and finish (see photographs)
CHAMBERS
HAVE ALL
SURFACES
COVERED WITH
RESISTIVE FOAM
PYRAMID
ABSORBERS
FULLY ANECHOIC
ANTENNA/MICROWAVE
(FREE SPACE) TEST CHAMBERS
Fully anechoic (free space) chambers are for antenna calibration and other
mid/high frequency applications such as satellite testing. These chambers
have all surfaces covered with resistive foam pyramid absorbers. Low back
scatter absorbers can be installed to further improve measurement accuracy.
The function of a fully anechoic test chamber is to copy or mimic free
space by using absorbers that have ‘progressive impedance’
this is, to prevent reflectivity by gradual absorbing the energies.
A fully anechoic chamber can be of any size depending on the requirement
but the pyramid absorbers need to be large enough to give the required
reflection loss at the required frequency (see pyramid absorber sheet)
With -50dB of reflection loss a measurement accuracy of <0.3dB can
be achieved.
Other important considerations to this type of chamber are:
Non- reflecting (plastic) lights which have cold operation.
Specific use of walkway
absorbers or plastic walkways.
No reflective edges around doors.
Hidden facility/ventilation panels.
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