Big news: GTG Group has completed the overall construction of 10-meter semi-anechoic chamber and will be put it into operation soon! Since then, GTG Group has become one of the few third-party testing institutions in China that owns both a 3-meter semi-anechoic chamber and a 10-meter semi-anechoic chamber.
Compared with the 3-meter semi-anechoic chamber, the 10-meter semi-anechoic chamber has a 3-meter or larger static zone, and the 10-meter semi-anechoic chamber can meet the requirements of radiated disturbance testing for large-size products, such as automobiles, large-size medical equipment and IT products, etc. Due to its better chamber performance, it becomes an ideal testing site for many EMC test standards, and fully meets the requirements of international certifications, such as FCC, CE, and VCCI.
In addition, GTG Group’s EMC test systems are imported from ROHDE & SCHWARZ, ETS-Lindgren and other international famous brands, which can provide customers with more comprehensive, more detailed and more accurate EMC tests.
If you are worried about not finding a professional and technologically advanced EMC testing organization yet, then GTG Group is your trustworthy partner, let our professionals test and verify any information for you at any time, and create safer products together!
What is anechoic chamber?
In order to standardize the electromagnetic compatibility of electronic or other products, it is necessary to carry out relevant electromagnetic compatibility tests according to the relevant international standards or national standards, and the place where electromagnetic compatibility tests are carried out is the electromagnetic compatibility laboratory. A complete system of electromagnetic compatibility laboratory generally includes two parts: a shielded room and an anechoic chamber. The shielded room is a hexahedral metal room with a spliced or welded structure, while the anechoic chamber is a place for radiated emission tests and radiated immunity tests on the basis of shielded room with wave absorbing material laid on the inner wall.
According to the test distance, the anechoic chamber is divided into 3m anechoic chamber and 10m anechoic chamber. 10m and 3m means the distance of the equipment under test (EUT) from the antenna. 10m anechoic chamber is generally referred to as the 10m semi-anechoic chamber, which refers to the other five surfaces except the ground are paved with wave-absorbing materials in a confined space, and the ground is a metal floor, which is able to simulate the reflection-free open space. The 10-meter semi-anechoic chamber, including radiated emissions testing, radiated immunity testing, conducted emissions testing, and conducted immunity testing. These tests are carried out to ensure that the device under test is compatible with other devices that are in the vicinity.
What are the standards that a 10-meter semi-anechoic chamber must meet?
A 10-meter semi-anechoic chamber must meet several standards, including CISPR 25, CISPR 16, and EN 61000-4-3. These standards ensure that the chamber provides a controlled environment for EMC testing and that the results are accurate.
Why 10-meter semi-anechoic chamber seldomly heard?
A 10-meter semi-anechoic chamber has several limitations.
- Firstly, it is expensive to construct and maintain.
- Secondly, it requires a significant amount of space, which may not be feasible for smaller companies.
- Lastly, it requires skilled personnel to operate it, which may be a challenge for some companies.
While it has several limitations, the benefits of using a 10-meter semi-anechoic chamber far outweigh the drawbacks.
Advantages of the 10m anechoic chamber
One of the obvious advantages of the 10m anechoic chamber is that the structure of the anechoic chamber is larger, the diameter of the turntable is larger, the load-bearing capacity is larger, the direction of the receiving antenna is more “intelligent”, and the test static zone is larger. The test error at low frequency is smaller. Specifically:
- Can test large-sized equipment: larger structure of the anechoic chamber and turntable diameter and static area, can accommodate a larger size of the sample, such as sample diameter more than 1.5 meters.
- Can test large weight equipment: larger turntable load bearing, can bear large tonnage samples, such as samples more than 3 ton.
- Smaller error, more accurate data: the 10-meter anechoic chamber can accurately measure the radiated disturbance data with frequency less than 1GHz. At present, many countries or regions no longer accept the test results of 3m anechoic chamber for radiation disturbance data below 1GHz.
Major performance indexes of 10m anechoic chamber
There are four main technical indexes of 10m anechoic chamber, which are normalized site attenuation, site voltage standing wave ratio, field uniformity and ambient noise.
1. Normalized Site Attenuation (NSA) Based on CISPR16-1-4
| Static Zone | 3.0m in diameter and 2.0m in height |
| Test Distance | 10.0m |
| Frequency Range | 30MHz-1GHz |
| NSA | ±2.8dB |
2. Site Voltage Standing Wave Ratio (SVSWR) Based on CISPR16-1-4
| Static Zone | 3.0m in diameter and 2.0m in height |
| Test Distance | 10.0m |
| Frequency Range | 1GHz-18GHz |
| SVSWR | ≤6.0dB |
3. Field Uniformity (FU) Base on IEC61000-4-3
| Test Area | 1.5m×1.5m，Center height 1.55m |
| Test Distance | 3.0m |
| Frequency Range | 30MHz-18GHz |
| FU | The maximum field strength difference of at least 12 of the 16 measuring points is within the range of 0dB-6.0dB. |
4. Ambient Noise (AN)
| Limits | Lower than 6.0dB based on CISPR22 Class B |
Configuration of GTG Group 10m anechoic chamber
1. The basic facilities and equipment of the 10m anechoic chamber
- A shielding shell: the internal size is 20.8m long*12.1m wide*9.0m high, constructed by American assembly technology, which ensures the shielding effectiveness, but also ensures the durability of the shielding room, and can be relocated or expanded.
- Platform screen door (PSD): 1.2m*1.2m and 3.0m*3.0m, manual operated.
- Waveguide vent: 8 waveguide windows in standard size 300mm×300mm (with flange), cut-off frequency 18GHz.
- Electrical system: 300W halogen lamps*8, 220V/single phase/socket, 380V/3 phase/socket.
- Filter: filtering power supply of 380V, 220V, 110V, DC, as well as signal of network & communication.
- Joint and joint plate: used to connect equipment in the control room, installed under the elevated floor. 2 sets of 300mm*300mm connector plates. N type connector, BNC type connector and SMA type connector are available.
- Elevated floor: maximum load 2000kg (2 ton), 50cm high.
- Wave absorbing materials: the wall absorbing material consists of ferrite (100mm×100mm× 6.7mm), a low-frequency wave absorbing material composed of nickel, zinc, iron and manganese, and ESSORB-VHY-30-NRL, a high-performance composite truncated conical wave absorbing material. The movable ground absorbing material consists of ESSORB-VHY-12-NRL and ferrite. The absorbing material can be covered with a white reflector to beautify the internal environment and increase brightness.
- CCTV: 2 sets of digital color surveillance systems, one set fixed on the wall and the other is movable on the ground. Both can withstand 100V/m field strength (DC-18MHz frequency range). The camera controller is connected with the camera through optical fiber to control the camera move up and down, zoom and focus.
2. Anechoic chamber measurement system
- Embedded EUT turntable: the turntable is controlled by fiber optics, avoiding the electromagnetic interference as all as possible.
- Size: 5 meters in diameter
- Material: metal structure, metal table
- Max. load: 5000kg (5 ton)
- Control: Electric drive. Positioning and rotation speed are remotely control outdoor.
- Rotation angle: 360 degrees clockwise and counterclockwise rotation, positioning tolerance lower than ± 10 degrees.
3. Antenna lifting tower
- Material: FRP
- Size: 6.3 meters high with horizontal and vertical polarization, various types of antennas can be installed.
- Control: signal transmitted via optical fiber.
- Dual-channel controller: control turntable and the movement of antenna.
4. EMI test software
GTG Group has always attached great importance to the improvement of product testing capabilities and innovation & upgrading of testing technologies. Not only establishing a fully independent testing center and an industry-advanced testing platform, but also continuously obtaining official authorization from well-known certification bodies at home and abroad to strengthen the laboratory system. As of 2023, GTG Group has been recognized and accredited by a number of renowned local and international certification bodies such as IECEE, UL, A2LA, NVLAP, ITS (Intertek), KTC, TÜV, Eurofins, CNAS, CMA, CQC and others.
In the future, GTG Group will continue to provide best-in-class product testing and certification services to help improve your business processes, increase customer satisfaction and reduce costs, while you can protect your brand, improve trust, and gain more visibility throughout your global supply chain.