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 : 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 3 rd party evidence of compliance
Price What is included? What is excluded? Commercial 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
9 Faraday s Law demo
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
11 EM Wave
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. 14
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 15
Main Shield Technologies Modular S81 Enclosure (Sandwitch) Modular S101 Enclosure (Pan-type) 16
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. 17
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. 18
Shielding Effectiveness typical SE values pending on door tpye / RF-components S81 Enclosure S101 Enclosure (RFD-100 door) 19
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 21
RF-Shielded Double Door 22
RF-Shielded Sliding Door 23
Anechoic Chamber Swing Door 24
Anechoic Chamber Sliding Door 25
Anechoic Chamber Sliding Door 26
Large Shielded Sliding Door 27
Shielded Enclosure Accessories 28
Shielded Enclosure Accessories Filter out of factory Stevenage, UK 29
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. 34
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. 35
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. 36
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. 37
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 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. 38
Turn-key Solution 39
Antennas
RF numerical modeling Mechanical design Fabrication 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!!! 47 / 91
Service Design & construction Project management On site project management / supervision Full installation / shield test Maintenance 48
Summary Chamber Capabilities Standard MIL STD 461 CISPR25 IEC 61000-4-3 CISPR 16-1-4 NSA CISPR 16-1-4 svswr 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 Pre- Compliant 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 Compliant 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