|
|
|
|
|
|
|
Anechoic Chambers
Anechoic means "neither having nor producing echoes." In applications discussed here, the echoes typically refer to RF and/or microwave reflections. An anechoic chamber is usually a modular shielded room (or occasionally a welded room) that is lined inside with RF and/or microwave absorbing ("anechoic") material. It is essentially a "stealth room" that is invisible to the products or tests being conducted inside. Depending on the purpose of the room, anechoic material may be placed on the walls and ceiling (usually referred to as "semi-anechoic") or it can be placed on all six sides of the room (aka "fully anechoic").
|
Construction
Supporting Structure
An anechoic chamber is normally a modular shielded room with additional structural steel to provide the necessary support for the additional weight of the anechoic material. See the web page on shielded rooms for more information about the construction of the shielded room and the options that are available.
RF/Microwave Absorber
The RF and microwave absorbing material is chosen based on the customer requirements. We offer a wide selection of polyurethane, polystyrene, polyethylene and ferrite absorbers as well as various combinations to suit each unique performance and environmental specification. Please see our web page on absorber for more information about our selections.
Electromagnetic Compatibility (EMC)
Anechoic Chambers
EMC chambers are designed to create a controlled environment in accordance with published specifications. An untreated modular shielded room is a resonant cavity with field variations up to 30dB. By incorporating anechoic material in specific designs and configurations, the same room can be controlled to within 3-8dB across a frequency range of 26MHz up to 1GHz, 18GHz or 40GHz (depending on the requirement) - a dramatic improvement on the reliability and consistency of test data acquired. Below is a list of common EMC Anechoic Chambers.
Compact Anechoic Chambers
The compact anechoic chamber is the smallest anechoic test facility recommended for performing EMC testing from 26MHz to 1GHz (with an option to go to 18GHz). This style of anechoic chamber allows the user to carry out radiated immunity measurements in full compliance with IEC 61000-4-3 / EN 61000-4-3 standards and pre-compliance emissions measurements for EN 50147-2, ANSI C63.4-2000 and CISPR 22. The chamber is comprised of a standard modular shielded enclosure, additional structural support and ferrite tile absorber on five sides. Compact anechoic chambers are guaranteed to provide a uniform field variation of less than 6dB when measured in accordance with IEC-61000-4-3. The option to go up to 18GHz requires the addition of foam absorber in specific locations on the walls and ceiling.
Features:
- Affordable EMC pre-compliance test solution
- Small size fits in most industrial buildings or office areas (Approx Size: 24' x 10' x 10'h)
- Fully compliant for European radiated immunity tests (IEC 61000-4-3 / EN 61000-4-3)
- Excellent for radiated emissions pre-scans and provides accurate correlation with Open Air Test Sites (OATS)
Standard Configuration:
- Modular shielded enclosure (Approx Size: 24' x 10' x 10'h)
- Structural package
- Dielectric vapor barrier and hardboard
- Ferrite tile absorber panels for walls, ceiling and 120 sq. ft. of floor area
- Safety net for ceiling
- One (1) single leaf 3' x 7' RF Shielded QuietDoor. c/w standard handle outside, phenolic handle on inside and door maintenance kit
- One (1) 12" x 12" brass bulkhead connector panel
- Two (2) 12" x 12" waveguide air vents
- Three (3) 1-1/4" brass waveguide penetrations c/w dielectric couplings for fire sprinklers
- Two (2) 2x30amp powerline filters
- One (1) brass ground stud
- Anti-static vinyl floor treatment
- RF shielding effectiveness test per IEEE299 at 1GHz
Options:
- Foam absorber to extend frequency to 18GHz
- Raised floor/ground plane
- Automated turntable (requires raised floor/ground plane)
- Complete ferrite treatment on floor and with corner strips
- Additional powerline and signal filters
- High hat lighting
- Field Uniformity Test (80MHz to 1GHz)
- Normalized Site Attenuation Test (30MHz to 2GHz)
3m Anechoic Chambers
3m anechoic chambers are ideally suited for performing both radiated emissions and radiated immunity EMC testing from 26MHz to 18GHz (with an option to go to 40GHz or higher). Like the compact chamber, this style of anechoic chamber allows the user to carry out radiated immunity measurements in full compliance with IEC 61000-4-3 and EN 61000-4-3 standards, but the full-scan capability of the 3m chamber allows fully compliant emissions measurements for many (but not all!) International and United States specifications. The chamber is comprised of a standard modular shielded enclosure, additional structural support and a combination of foam and ferrite tile absorber on five sides. 3m anechoic chambers are guaranteed to provide a uniform field variation of less than 6dB when measured in accordance with IEC-61000-4-3 and to exhibit a normalized site attenuation within +/- 4dB of the theoretical normalized site attenuation. The standard configuration provides a "quiet zone" of 6' diameter x 6' high, but this can be enlarged at the customer's request. The option to go up to 40GHz requires additional foam absorber and special floor treatment.
Features:
- Fully compliant for testing radiated emissions per EN 50147-2, ANSI C63.4-2000 (part 15 and 18), CISPR 22 / EN 55022, EN 50147-2 and can be registered with FCC as 3m Class B Facility
- Fully compliant for European radiated immunity tests per IEC 61000-4-3 / EN 61000-4-3
- Provides accurate correlation with Open Air Test Sites (OATS)
Standard Configuration:
- Modular shielded enclosure (Approx Size: 32' x 24' x 21'h)
- Structural package
- Dielectric vapor barrier and hardboard
- Ferrite tile absorber panels for walls, ceiling and 120 sq. ft. of floor area
- Foam absorber for walls and ceiling
- Safety net for ceiling
- One (1) single leaf 3' x 7' RF Shielded QuietDoor. c/w standard handle outside, phenolic handle on inside and door maintenance kit
- 1.5m automated turntable and controller
- One (1) 12" x 12" brass bulkhead connector panel
- Four (4) 12" x 12" waveguide air vents
- Three (3) 1-1/4" brass waveguide penetrations c/w dielectric couplings for fire sprinklers
- Two (2) 2x30amp powerline filters
- One (1) brass ground stud
- Raised ground plane
- RF shielding effectiveness test per IEEE299 at 1GHz
Options:
- Separate shielded control room
- Room modifications and additional foam absorber to extend frequency to 40GHz
- Larger automated turntables
- Additional and/or larger shielded doors
- Additional powerline and signal filters
- High hat lighting
- Field Uniformity Test (80MHz to 1GHz)
- Normalized Site Attenuation Test (30MHz to 2GHz)
5m Anechoic Chambers
5m anechoic chambers offer all the same benefits of 3m chambers, but offer greater accuracy and correlation with OATS and 10m readings. They are ideally suited for performing both radiated emissions and radiated immunity EMC testing from 26MHz to 18GHz (with an option to go to 40GHz or higher). They allow the user to carry out radiated immunity measurements in full compliance with IEC 61000-4-3 and EN 61000-4-3 standards and fully compliant emissions measurements for many (but not all!) International and United States specifications. The chamber is comprised of a standard modular shielded enclosure, additional structural support and a combination of foam and ferrite tile absorber on five sides. 5m anechoic chambers are guaranteed to provide a uniform field variation of less than 6dB when measured in accordance with IEC-61000-4-3 and to exhibit a normalized site attenuation within +/- 4dB of the theoretical normalized site attenuation. The standard configuration provides a "quiet zone" of 6' diameter x 6' high, but this can be enlarged at the customer's request. The option to go up to 40GHz requires additional foam absorber and special floor treatment.
Features:
- Fully compliant for testing radiated emissions per EN 50147-2, ANSI C63.4-2000 (part 15 and 18), CISPR 22 / EN 55022, EN 50147-2 and can be registered with FCC as 3m Class B Facility
- Fully compliant for European radiated immunity tests per IEC 61000-4-3 / EN 61000-4-3
- Provides accurate correlation with Open Air Test Sites (OATS)
Standard Configuration:
- Modular shielded enclosure (Approx Size: 43' x 26' x 21'h)
- Structural package
- Dielectric vapor barrier and hardboard
- Ferrite tile absorber panels for walls, ceiling and 120 sq. ft. of floor area
- Foam absorber for walls and ceiling
- Safety net for ceiling
- One (1) single leaf 3' x 7' RF Shielded QuietDoor. c/w standard handle outside, phenolic handle on inside and door maintenance kit
- 1.5m automated turntable and controller
- One (1) 12" x 12" brass bulkhead connector panel
- Four (4) 12" x 12" waveguide air vents
- Three (3) 1-1/4" brass waveguide penetrations c/w dielectric couplings for fire sprinklers
- Two (2) 2x30amp powerline filters
- One (1) brass ground stud
- Raised ground plane
- RF shielding effectiveness test per IEEE299 at 1GHz
Options:
- Separate shielded control room
- Room modifications and additional foam absorber to extend frequency to 40GHz
- Larger automated turntables
- Additional and/or larger shielded doors
- Additional powerline and signal filters
- High hat lighting
- Field Uniformity Test (80MHz to 1GHz)
- Normalized Site Attenuation Test (30MHz to 2GHz)
10m Anechoic Chambers
10m anechoic chambers are designed to perform radiated emissions measurements at 10 meter distance in full compliance with most international standards. They are also ideally suited for performing radiated immunity tests in full compliance with IEC 61000-4-3 and EN 61000-4-3 standards. The chamber is comprised of a standard modular shielded enclosure, additional structural support and a combination of foam and ferrite tile absorber on five sides. 10m anechoic chambers are guaranteed to provide a uniform field variation of less than 6dB when measured in accordance with IEC-61000-4-3 and to exhibit a normalized site attenuation within +/- 4dB of the theoretical normalized site attenuation. The standard configuration provides a "quiet zone" of 6' diameter x 6' high, but this can be enlarged at the customer's request. The option to go up to 40GHz requires additional foam absorber and special floor treatment.
Features:
- Fully compliant for testing radiated emissions per EN 50147-2, ANSI C63.4-2000 (part 15 and 18), CISPR 22 / EN 55022, EN 50147-2 and can be registered with FCC as 3m and 10m Class A and B Facility
- Fully compliant for European radiated immunity tests per IEC 61000-4-3 / EN 61000-4-3
- Provides accurate correlation with Open Air Test Sites (OATS)
Standard Configuration:
- Modular shielded enclosure (Approx Size: 62' x 40' x 28'h)
- Structural package
- Dielectric vapor barrier and hardboard
- Ferrite tile absorber panels for walls, ceiling and 120 sq. ft. of floor area
- Foam absorber for walls and ceiling
- Safety net for ceiling
- One (1) single leaf 3' x 7' RF Shielded QuietDoor. c/w standard handle outside, phenolic handle on inside and door maintenance kit
- 1.5m automated turntable and controller
- One (1) 12" x 12" brass bulkhead connector panel
- Four (4) 12" x 12" waveguide air vents
- Three (3) 1-1/4" brass waveguide penetrations c/w dielectric couplings for fire sprinklers
- Two (2) 2x30amp powerline filters
- One (1) brass ground stud
- Raised ground plane
- RF shielding effectiveness test per IEEE299 at 1GHz
Options:
- Separate shielded control room
- Room modifications and additional foam absorber to extend frequency to 40GHz
- Larger automated turntables
- Additional and/or larger shielded doors
- Additional powerline and signal filters
- High hat lighting
- Field Uniformity Test (80MHz to 1GHz)
- Normalized Site Attenuation Test (30MHz to 2GHz)
Mil-Std 461E Anechoic Chambers
The Mil-Std-461E anechoic chamber is designed specifically for Mil-Std testing. The chamber is comprised of a standard modular shielded enclosure, additional structural support and ferrite tile absorber on five sides. Mil-Std-461E chambers are guaranteed to provide 6dB reflectivity loss between 80MHz and 250MHz.
Features:
- Fully compliant for Mil-Std-461E (and earlier versions) emissions and susceptibility testing for both radiated and conducted specifications
- Provides 6dB reflectivity loss from 80MHz - 250MHz (extended frequencies available)
Standard Configuration:
- Modular shielded enclosure (Approx Size: 20' x 20' x 12'h)
- Structural package
- Dielectric vapor barrier and hardboard
- Foam absorber
- One (1) single leaf 3' x 7' RF Shielded QuietDoor. c/w standard handles and door maintenance kit
- One (1) 12" x 12" brass bulkhead connector panel
- Two (2) 12" x 12" waveguide air vents
- Three (3) 1-1/4" brass waveguide penetrations c/w dielectric couplings for fire sprinklers
- Two (2) 2x30amp powerline filters
- One (1) brass ground stud
- Anti-static vinyl floor treatment
- RF shielding effectiveness test per Mil-Std-285 at 1GHz
Options:
- Additional powerline and signal filters
- Shielded control room
Antenna Pattern Chambers
Rectangular Chambers
Ideally suited for performing a variety of measurements, rectangular chambers are typically designed to meet the increased performance demands of today's wireless and far-field antenna measurement applications. They also provide an excellent test environment for antenna pattern, monostatic and bi-static RCS measurements, and both fixed frequency and swept frequency operations. Seeker facilities with phased arrays are also best housed in a rectangular facility.
Performance of rectangular anechoic chambers is defined by reflectivity as a function of frequency for a relatively small volume within the facility ( the "quiet zone"). The quiet zone is normally positioned longitudinally in the chamber with the edge of the quiet zone no closer than three feet from the end wall absorbers. The test region diameter is reduced as the test frequency increases.
The dimensions and geometry of a rectangular anechoic chamber are generally dictated by the distance between the device under test and the transmit/receive antenna and frequency of operation. The performance of a rectangular anechoic chamber is defined by comparing a direct signal with the reflected signal either from one surface or as the vector sum of the reflections from all chamber surfaces. By lining the rectangular chamber end walls with high-performance foam and ferrite absorber material and controlling side wall reflections with absorbers of increased sizes in the specular regions, our rectangular chambers deliver exceptional accuracy for low frequency measurements (down to 700 MHz with foam absorber only and 26 MHz with ferrite absorber).
The quiet zone of all our rectangular anechoic chambers is guaranteed to meet specified performance levels. The "Free Space VSWR" procedure is used to evaluate the quiet zone performance by transversely and longitudinally crossing the test region at incremental angles of the receive probe antenna. This validation technique measures the standing wave set up by the interference of direct signal and the vector sum of the signals from the chamber absorbers. A performance test report is provided as a testament to our performance guarantee.
Standard Configuration
- 100 dB modular shielding
- Free-standing structural support
- 100 Amp AC power line filters
- RF-shielded lighting system
- RF waveguide air vents
- RF penetration panels
- RF shielded doors
- High-performance absorber treatment
Options
- Control room
- Automated sliding doors
- Electric power distribution
- CCTV system
- HVAC system
- Architectural finishes
- Mechanical absorber mounting
Specifications:
| Model: |
DJM-RA-200 |
DJM-RA-300 |
DJM-RA-400 |
DJM-RA-500 |
| Nominal Dimensions (LxWxH) |
24'x12'x12' |
26'x14'x14' |
32'x16'x16' |
36'x18'x18' |
| Quiet Zone Size |
2.0' |
3.0' |
4.0' |
5.0' |
| Range Length |
14.0' |
18.0' |
22.0' |
28.0' |
Tapered Chambers
Tapered anechoic chambers are primarily designed for low-frequency applications associated with antenna patterns and monostatic RCS measurements. However, their unique design makes them suitable for meeting the increased performance demands of today's wireless and general purpose antenna measurement applications.
The tapered chamber is a spherical antenna range configured with one side transitioning from a square chamber to a rounded chamber and eventually a true conical section. The tapering walls bring reflections into phase coherency so that they are all in phase at the test region (the "quiet zone"). The energy is transmitted from the conical section toward the terminating end wall absorbers at normal and near normal incidence. Chamber reflections and extraneous energy in the quiet zone are determined primarily by the reflectivity performance of the pyramidal absorber on the end wall. By designing the chamber with high performance terminating wall absorbers, our tapered anechoic chambers deliver greater accuracy for low frequency measurements (down to 200 MHz).
The quiet zone is centered longitudinally in the square section of the chamber, provided that the edge of the quiet zone is no closer than three feet from the end wall absorbers. Test region diameter is reduced as the test frequency increases.
The tapered chamber uses antenna source imaging as the driving force necessary to launch energy down the taper. To optimize far-field measurement performance, our tapered chambers utilize custom-built feed antennas. The characteristics of these feed antennas provide a smooth pattern without singularities within the feed angle of the conical section. The feed system comes equipped with a feed antenna positioner to allow precise boresight alignment on the test antenna.
Standard Configuration
- 100 dB modular shielding
- Free-standing structural support
- 100 Amp AC power line filters
- RF-shielded lighting system
- RF waveguide air vents
- RF penetration panels
- RF shielded doors
- High-performance absorber treatment
Options
- Control room
- Automated sliding doors
- Electric power distribution
- CCTV system
- HVAC system
- Architectural finishes
- Mechanical absorber mounting
Specifications:
| Model: |
DJM-AETA-300 |
DJM-AETA-400 |
DJM-AETA-500 |
DJM-AETA-600 |
| Nominal Dimensions (LxWxH) |
28'x10'x10' |
36'x13'x13' |
42'x15'x15' |
56'x18'x18' |
| Quiet Zone Size |
3.0' |
3.5' |
4.0' |
5.5' |
| Range Length |
20.0' |
26.0' |
30.0' |
42.0' |
Millimeter Wave Chambers
Millimeter wave anechoic chambers are a new and exciting area of testing. Due to the extremely short wavelengths involved, millimeter wave chambers require the materials used in their construction to perform consistently, piece to piece. The base foam material, as well as the impregnation dispersions, must be carefully selected and controlled to ensure that the materials are homogenously loaded. Millimeter-wave chambers are predominately rectangular shaped because the antennas are highly directive, which contributes significantly to the design ultimately used.
Double Horn Anechoic Chambers
Double horn anechoic chambers are designed for optimum performance under conditions where conventional tapered or rectangular chambers are impractical due to either size or cost. A patented design, the double horn chamber combines features of both tapered and rectangular chambers, but does not suffer from performance deterioration caused by high reflectivity of radiation off chamber walls, high aspect ratios or low angles of incidence.
|
|
|
|
