Anechoic chamber from ETS

Anechoic chamber
from
ETS-Lindgren
25.09.2013 Moscow
26.09.2013 Peterburg
Lukasz Wilk
1
Production Plant Eura, FI
2
Overall Assessment
An anechoic chamber is a construction project that can
take several months to complete.
It is usually a significant investment with a projected life
cycle of typically > 10 years.
In order to make the right choice a potential buyer should
assess the supplier on the following issues :
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Project capability
Technical performance
Commercial conditions
Financial risk
Project Capability
• Supplier’s Reference list
• Supplier’s Mechanical engineering/design
capability
• Supplier’s Manufacturing capability
• Supplier’s Installation capability
• Supplier’s RF engineering/design capability
• 3rd party evidence of compliance
Commercial
• Price
– What is included ?
– What is excluded ?
• Terms and Conditions
– Warranty
– Delivery schedule
• Sub contract
– How much of the scope is sub contracted
Financial Risk
• Ability to complete the project
– Size of company vs project value
– Credit limit
– Assets
– Debt
• Ability to support after sales service
– Spare parts
– Maintenance
Buying from a low bidder
• Price is low – Why ?
• Hidden costs ?
• Risk is higher ?
– Lower quality
• Unable to service/maintenance = lost revenue
– Smaller company
– Long term issues
• Unable to service/maintenance = lost revenue
– Delivery issues
• Delays = extra costs/lost revenue
– Extra cost involved in managing the project
Michael Faraday (1791-1867)
Faraday was a British chemist and physicist
who contributed significantly to the study of
electromagnetism and electrochemistry.
8
Faraday’s Law demo
9
Magnetic Field Lines Around a Wire,
Magnetic Field
http://www.m
agnet.fsu.ed
u/education/t
utorials/java/
fieldlines/ind
ex.html
Current
Wire
10
EM Wave
11
WAVES
Sinusoidal waves of various frequencies; the bottom waves have higher frequencies
than those above. The horizontal axis represents time.
12
13
Basics
wavelength = Speed of light / Frequency
Wavelength :
Speed of light :
Frequency:
metres
300 000 000 metres per second
(108 Million Km/h)
Hz
Faraday cage
• A Faraday cage is an
enclosure formed by
conducting material, or
by a mesh of such
material.
• Such an enclosure
blocks out external static
electrical fields.
• Faraday cages are
named after physicist
Michael Faraday, who
built one in 1836.
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Faraday cage
• Electronic components or
systems that require an
environment free of
electromagnetic interference
may be done a so-called
screen room.
• These screen rooms are
completely enclosed by sheet
metal.
• The metal layers are
connected to earth ground to
dissipate any electric currents
generated from the external
electromagnetic fields
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Main Shield Technologies
Modular S81 Enclosure (Sandwitch)
Modular S101 Enclosure (Pan-type)
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Modular S81 Panels
Construction
The Series 81 Shielded Enclosure consists of shielded modular
panel sections that are assembled with a clamping system into a
self-supporting room structure. Sheets of 28-gauge galvanized
steel are laminated to a 3/4-inch, high-density particle and/or
plywood board core. Each panel section provides excellent
stability to airborne moisture-induced warping and structure
strength that lend to its rugged structural design.
Series 81 panels are joined together with an extruded “hat and
flat” and “cove” clamping system to provide uniform and consistent
pressure contact against the shielded panel mating surfaces.
These structural clamping sections are zinc-plated to resist
corrosion and are joined with self-taping zinc-plated fasteners
spaced four inches on center to ensure a secure shield. The
corners of the shielded room are secured with precision-machined
trihedral end cap sections.
To maintain electrical isolation, a 6-mil dielectric vapor barrier and
1/8" dielectric underlayment are placed beneath the shielded floor
panels. Counter-sunk floor screws in the clamping system ensure
a smooth floor surface. Attractive vinyl floor tiles are applied with
adhesives over the exposed steel surface as a durable wearing
surface. In addition, the Series 81 enclosure can be converted into
a ferrite-lined and/or conventional absorber-lined anechoic
chamber. This feature makes it a truly flexible shielding solution.
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Modular S101 Panels
Description
The Series 101 rooms can be dismantled and reinstalled, enlarged or modified due to the
panel system. Only the gasket and the fasteners have to be replaced. No special tools nor
welding are necessary during the installation. No maintenance is necessary after installation.
The modular structure allows for very flexible adaptation to the customer's needs and
requirements. Both the size and shape of the room can be designed to meet the individual
needs of the customer. As only the system (distance of holes and increments in the outer
dimensions) and the panel joint are standardized, Series 101 is not limited to the use of only a
few standard size panels. However, the automated manufacturing technology utilizes the
advantages of high quantity production of standardized panels.
The same manufacturing technology can be applied to different materials such as hot
galvanized steel and aluminum. The requirements can be realized by using same machinery,
thus enabling cost-effective solutions and a competitive price-quality-ratio.
The panel system provides a reliable and high performance shielding, as the panels are
jointed with special gasket. However, at the same time the number of fasteners can be
minimized, which also shortens the assembly time.
The Series 101 panels can be bolted from inside or from outside, depending on the purpose
and requirements. The shielded room can also include a combination of flat sides inside and
outside.
When installing the enclosure from inside (flat side outside), the enclosure can be assembled
in close proximity(e.g. without a supporting structure as close as 5 cm) of existing walls of the
parent building and the panel bendings (flanges) can be used for installing inner lining or
absorber rails when appropriate.
When installing the enclosure from outside (flat side inside), the hanging from the support
structure does not penetrate the shielding and the inside is flat. This is required in partial
discharge / high voltage testing halls as well as when either ferrites or absorbers are glued
directly onto the walls and ceiling. Please note that the space required for the installation work
is about 800 mm all around, also above the roof.
As the Series 101 corner joint is identical to the intermediate joint no additional supports or
special constructions are needed. The corners have equally reliable attenuation as the rest of
the enclosure. Electromagnetic interference has no chance: no way in or no way out, as the
case may be. This is just an example epitomizing that the Series 101 enclosure forms a
carefully designed entity with painstaking attention to detail.
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Shielding Effectiveness
typical SE values pending on door tpye / RF-components
S81 Enclosure
S101 Enclosure (RFD-100 door)
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Field
Frequency
Pan
(S101)
Sandwich
(S81)
Magnetic
1 kHz
45 dB
20 dB
Magnetic
10 kHz
85 dB
56 dB
Magnetic
100 kHz
105 dB
100 dB
Magnetic
1 MHz
120 dB
110 dB
Magnetic
10 MHz
125 dB
110 dB
Electric
100 MHz
125 dB
110 dB
Electric
1 GHz
125 dB
110 dB
Plane Wave
10 GHz
125 dB
100 dB
Plane Wave
18 GHz
125 dB
80 dB
Plane Wave
40 GHz
125 dB
-
Note : Performances stated must be measured without absorber
Basic Swing Doors
S501 Door for S81 Enclosure
RFD Door for S101 Enclosure
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RF-Shielded Double Door
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RF-Shielded Sliding Door
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Anechoic Chamber Swing Door
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Anechoic Chamber Sliding Door
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Anechoic Chamber Sliding Door
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Large Shielded Sliding Door
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Shielded Enclosure Accessories
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Shielded Enclosure Accessories
Filter out of factory Stevenage, UK
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The Absorber Family
1
Ferrite Tile .
Magnetic Losses
Preferred technology
for Low frequencies (up
to 2GHz), it has low
profile (7mm max).
It cannot be used for
high frequencies
The Absorber Family
2
Microwave
Pyramidal absorber.
Electric Losses
Preferred technology
for High frequencies
It can be used for low
frequencies if size
(length) is increased
The Absorber Family
3 Hybrid Absorber .
Electric and Magnetic Losses
Preferred technology for EMC
Applications. foam has to have
special low carbon content for
good matching with ferrite tile
at the bottom.
At High frequencies its
performance is not as good as
MW pyramid of equal size.
Anechoic Chambers
• An anechoic chamber is
a shielded room designed
to attenuate waves.
• An RF anechoic chamber
is designed to suppress
the reflected
electromagnetic waves,
from the internal surfaces.
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Anechoic Chambers
• In a well-designed anechoic
chamber, the equipment
under test receive RF
signals from the signal
source, not reflected from
another part of the
chamber.
• This ensures the integrity of
the testing being
conducted.
• Furthermore, the shielding
of the chamber limits
interference from
equipment located outside
of the chamber.
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Anechoic Chambers
• They are lined with an absorbent
material, such as carbonimpregnated foam shaped into
pyramids.
• The pyramidal shape acts to resist
and dissipate the electromagnetic
waves.
• Testing is done in anechoic
chambers to analyze the
properties of antennas and other
electronics that are susceptible to
radio or microwave interference.
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Anechoic Chambers
• Anechoic chambers range
from small compartments to
chambers as large as aircraft
hangars.
• The size of an anechoic
chamber depends on the size
of the objects to be tested and
the frequency range of the
radio or microwave signals
used.
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Anechoic Chambers
•
•
Radio frequency interference (RFI) is
the unwanted reception of radio signals
and can be problematic to the other
electronic equipment onboard aircraft
and other vehicles.
Radio frequency interference sources
include
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–
–
–
•
lightning,
electrical equipment,
fluorescent lighting,
cell phones,
and transmitting equipment from radio
stations.
RFI testing helps determine which
frequencies affect particular electronic
systems and provide clues to reducing
the risks to communication devices or
developing measures to counter the
interference.
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Turn-key Solution
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Antennas
RF
numerical
modeling
Fabrication
Mechanical
design
Measurement
Low frequency
immunity horns
EMC / OTA Positioners
EMC Field Sensors
Shielded Doors, CCTV Cameras and
Filters
Products made from various sources are
never perfect in terms of compliance
Don’t like it, choose ETS-Lindgren.
Designed, made, installed with related test equipment: ETS-Lindgren !!!
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Service
 Design & construction
 Project management
 On site project management / supervision
 Full installation / shield test
 Maintenance
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Summary Chamber Capabilities
CISPR 16-1-4
sVSWR
CISPR 16-1-4
NSA
Compliant
IEC 61000-4-3
Pre- Compliant
CISPR25
MIL STD 461
Standard
Distance
1m
1m
3m*
3m
5m
10m
3m
5m
10m
Chamber Test
T
T
R
R
R
R
R
R
R
Start Frequency
80MHz
70MHz
80MHz
30MHz
30MHz
30MHz
1GHz
1GHz
1GHz
Stop Frequency
40GHz
2.5GHz
6GHz
1GHz
1GHz
1GHz
6GHz
6GHz
6GHz
Compact
T
T
R
T
T
T
T
T
T
MIL STD 461
R
T
T
T
T
T
T
T
T
CISPR 25
R
R
T
T
T
T
T
T
T
3 meter
R
R
R
R
T
T
R
T
T
5 meter
R
R
R
R
R
T
R
R
T
10 meter
R
R
R
R
R
R
R
R
R