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GB4824-2013 after the version of the darkroom and antenna requirements change

Release time:

2015-05-22 00:00

Source:

　　The new version of GB4824-2013 replaced the previous version of GB4824-2004, and was officially implemented on January 13, 2015.

　　Compared with the previous version, the GB4824-2013 version has a clear limit for the size of the EUT corresponding to the darkroom. In the old standard radiated emission test, the B-type equipment allows the 3m test, but the A-type equipment only allows the 10m test, because Class A equipment is mostly used in industrial environments, and most of them are large-scale equipment. The near-field effect must exist in the 3 m method test to affect the test results. Due to the high cost of the 10 m method anechoic chamber, this provision of the standard restricts the testing of Class A equipment for many laboratories; after the implementation of the new standard, the radiation emission test of Class A equipment is more clear, allowing small equipment ( 1.2 m x 1.5 m, diameter x height) is tested by the 3 m method, but Class A equipment exceeding this size must be tested by the 10 m method.

　　At the same time, the conditions of use of the antenna stipulated in the new standard:

　　7.3.4.2 30MHz~1GHz frequency band

　　In the 30MHz~1GHz frequency band, the antenna specified in IEC/CISPR 16-1-4 should be used, and the measurement should be carried out in the horizontal and vertical polarization directions. The lowest point of the antenna should not be less than 0.2m from the ground.

　　When measuring on the test site, the center of the antenna should be changed at a height of 1m~4m, so as to obtain the maximum indication value at each measurement frequency point.

　　On-site measurement, the center of the antenna should be fixed at a height of 2.0m±0.2m above the ground.

　　Note: Other types of antennas can also be used as long as the difference between the measured results and the balanced dipole antenna measured results is within ±2dB.

　　This means that the height of the vibrator of the antenna cannot be greater than 1.6m, because the antenna needs to be raised and lowered in the range of 1-4m during the radiation emission test. When the height of the antenna is 1 meter, if the height of the antenna vibrator is greater than 1.6m, the distance The height of the ground must be less than 0.2m, which means that the receiving antenna and transmitting antenna used in some anechoic chambers are often the same antenna, which cannot meet the standard test in many cases and must be replaced.

　　The size of a typical transmit/receive antenna HL562 is 0.6 m × 1.65 m × 1.68 m　　

　　The size of a typical transmit/receive antenna HL046E is 1.50 m × 1.50 m × 1.81 m

　　

　　This means that the transmitting antenna and the anti-interference antenna must be two antennas. The antenna used for transmitting requires a small size, which also means that the gain is small and cannot be used for transmitting. A typical receiving antenna such as Schwarzbeck's VULB9162 has a size of 1.5 ×0.92×0.62 meters, typical gain: 6.4±1.2dBi:

　　The antenna used for radiation immunity usually has a gain higher than 9dBi. A typical example is Schwarzbeck's STLP9128E, with a typical gain of 9+0.8/-1.5dBi. For radiation immunity systems, when other conditions remain unchanged , by increasing the gain of the antenna, the field strength level can be significantly improved, and the demand for the output power of the power amplifier can be reduced.

　　Typical radiated emission test site requirements are as follows:

　　A typical radiated emission test does not require absorbing materials on the ground below 1GHz, and the metal ground is directly used. The antenna distance is selected to be 3 meters or 10 meters according to the size of the product under test.

　　When the radiation emission test is greater than 1GHz, the ground needs absorbing materials. The typical layout is as follows. The required distance between the antenna and the product under test is 3 meters:

　

　　The typical radiation immunity test layout is as follows. The current IEC61000-4-3 requires a frequency range of 80MHz-6Gz, and the typical distance between the antenna and the tested product is 3 meters or 1 meter (above 1GHz):

　

　　This means that if a typical product test in an anechoic chamber needs to simultaneously perform radiated emissions below 1 GHz, radiated emissions above 1 GHz, and the radiated immunity test required by IEC61000-4-3, at least three layout changes are required, namely :

　　1. No absorbing material is laid on the ground for radiation emission test below 1GHz;

　　2. Add ground absorbing materials for radiation emission test above 1GHz;

　　3. Replace the absorbing material required for radiation immunity to conduct IEC61000-4-3 radiation immunity test;

　　Since the radiated emission test and the radiated immunity test are both routine test items and take a long time, and the pass rate of these two items is relatively the lowest, so how to improve the utilization rate of the darkroom has become an urgent need In response to this dilemma, Germany's Frankonia (Frankonia) Group has launched the latest SAC-10 Triton ten-meter darkroom, which can completely solve the problem of low efficiency. It can be used without changing the layout of the darkroom without moving the tested product Complete the radiation emission below 1GHz, radiation emission above 1GHz, and IEC61000-4-3 radiation immunity tests at one time, which greatly facilitates testing and improves efficiency.

　　The name of SAC-10 TRITON comes from:

　　T—Time saving time saving

　　R—Reproducibility Reproducible

　　I—Innovative concept Innovation

　　T—Trend-setting mainstream

　　O—Operational efficiency

　　N—Next generation New generation

　　The overall laboratory layout is as follows:

　　

　　At the same time, the performance of the anechoic chamber is also excellent. The NSA is not greater than ±2.5 dB, and the SVSWR is not greater than 5dB within a distance of 3 meters. With the unique absorbing material with excellent non-combustibility performance, FU and noise floor also fully meet the standard requirements.

　　The implementation of GB4824-2013 means that a new round of 10-meter darkroom construction is about to start, and Frankonia's unique SAC-10 TRITON darkroom will definitely be greatly recognized by customers.

Century Wisdom (Suzhou) Testing Technology Co., Ltd

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