Application of EMC Antenna and Near Field Probe in EMCEMI Pre-Test

1. Why do you need to perform EMC compliance pre-test?

With the development of electrical and electronic technology, household appliances are increasingly popular and electronic, radio and television, postal and telecommunications and computer networks are increasingly developed, and the electromagnetic environment is increasingly complicated and deteriorated, making electromagnetic compatibility of electrical and electronic products (EMC electromagnetic interference EMI and Electromagnetic anti-EMS) issues are also receiving increasing attention from governments and manufacturing companies. Electromagnetic compatibility (EMC) of electronic and electrical products is a very important quality indicator. It is not only related to the reliability and safety of the product itself, but also affects the normal operation of other equipment and systems. Protection of the electromagnetic environment. In order to regulate the electromagnetic compatibility of electronic products, all developed countries and some developing countries have developed electromagnetic compatibility standards. The electromagnetic compatibility standard is the basic requirement for the product to work properly in the actual electromagnetic environment. It is called the basic requirement, that is, even if the product meets the electromagnetic compatibility standard, interference may occur in actual use. Most national standards are based on standards set by the International Electrotechnical Commission (IEC).

The European Community Government stipulates that from January 1, 1996, all electrical and electronic products must pass EMC certification and be affixed with the CE mark before they can be sold in the European Community market. The move has caused widespread influence in the world, and governments have taken measures to implement mandatory management of EMC performance of electrical and electronic products. Internationally influential, such as the EU Directive 2004/108/EC (ie the EMC Directive) and the US Federal Code CFR 47/FCC Rules, all set clear requirements for EMC certification.

EMC (Electromagne TIc CompaTIbility) is electromagnetic compatible and includes EMI (electromagnetic disturbance) and EMS (electromagnetic anti-harassment). EMC is defined as the ability of a device or system to function properly in its electromagnetic environment without posing unacceptable electromagnetic disturbances to anything in any device in the environment. EMC's overall name is electromagnetic compatibility. EMP refers to electromagnetic pulses.

EMC = EMI + EMS (EMI : Electromagnetic Interference EMS : Electromagnetic Capacitive)

The National Radio Interference Standards Technical Committee and the National Electromagnetic Compatibility Standardization Technical Committee and other standardization bodies have developed a series of EMC standards (the same is true in Europe and the United States), such as some major product categories: EMC standards: Information Technology Equipment (ITE); Household and commercial equipment; Industrial equipment; communication equipment; radio; television receivers and related equipment; traction transport equipment; utility equipment (electricity, gas, water, etc.); medical equipment; measuring and testing equipment; equipment connected to medium voltage and high voltage public power supply systems .

Second, commonly used typical product standards

GB 4824-2004 "Industrial, scientific, medical (ISM) radio frequency equipment electromagnetic disturbance characteristics measurement methods and limits" (EN55011); GB 9254-2008 "Information technology equipment radio disturbance limits and measurement methods" (EN55022); GB 4824-2004 "Industrial, Scientific, Medical (ISM) RF Equipment Electromagnetic Disturbance Characteristics Measurement Methods and Limits" specifies limits for electromagnetic disturbance characteristics of industrial, scientific and medical (ISM) equipment and electrical discharge machining (EDM) and arc welding equipment Values ​​and measurement methods; This standard specifies the limits and measurement methods for RF disturbances in the frequency range of 9 kHz to 400 GHz. It is also applicable to engineering (ISM) lighting equipment operating at 2.45 GHz and 5.8 GHz in the medical technology band. The radio disturbance limit of information technology equipment in GB 9254-2008 "Radio Disturbance Limits and Measurement Methods for Information Technology Equipment" is considered to guarantee the appropriate emission level to protect radio broadcasting and telecommunication services, and allows Other equipment shall operate at a reasonable distance according to predetermined requirements; Information Technology Equipment (ITE) may include data processing equipment, office equipment, electronic commercial equipment, telecommunications equipment, etc. (with radio transmission and (as defined in the ITU Radio Regulations) Or any device that receives the function should meet the national radio specification, regardless of whether CISPR22 is valid or not.

Third, recommend Anoni products to solve the EMC / EMI electromagnetic compatibility and electromagnetic interference test difficulties

Instruments and systems for electromagnetic compatibility certification compliance testing are currently available on the market, often at very high prices, and require the establishment of a highly specialized electromagnetic compatibility laboratory or rental laboratory with high input costs and cumbersome testing procedures. Therefore, in the research and development of new products, in order to obtain EMC-related certifications, it is often rushed back and forth between the EMC certification laboratory and the company's R&D department, constantly redesigning, rectifying, and retesting. The enterprise is not able to leave the factory because the electromagnetic radiation disturbance intensity exceeds the electromagnetic compatibility standard, or the system cannot work normally due to electromagnetic interference between the circuit modules, thus delaying the listing of the product and worrying. Therefore, it is very necessary for engineers to conduct compliance pre-tests during the product development phase during the design period to ensure that the electromagnetic radiation measurement results of the developed products meet the electromagnetic radiation regulations and product launch progress.

It is strongly recommended to use the EMC/EMI electromagnetic compatibility and electromagnetic interference test program composed of the original imported German Alonia AG electromagnetic compatibility test spectrum analyzer and related EMC antenna and near field probe set to quickly find serious EMI interference. The problem is to quickly determine whether the product meets the corresponding EMC standards, thus helping engineers to determine the best, economical and efficient electromagnetic compatibility electromagnetic interference rectification plan for the products developed.

The Anoni electromagnetic compatibility test spectrum analyzer is very affordable and easy to operate. It provides a very rich test spectrum PC software for testing and comparison, and stores historical test data. The software has built-in various EMC-related standards and restrictions, which are convenient and simple to judge the existing problems. The various EMC test receiving antennas of Anoni are very compact, with excellent frequency response, matching calibration data, and very affordable price. It is suitable for all kinds of spectrum analyzers or receivers. It is the best receiving antenna for high-end spectrum analyzers. select. At present, many KEYSIGHT Keysight (formerly Agilent) customers use Anoni's receiving antennas for various tests.

Fourth, Anoni electromagnetic compatibility and electromagnetic interference EMC & EMI pre-test equipment configuration and main parameters

1) Host: Electromagnetic compatibility test spectrum analyzer (electromagnetic radiation test spectrum analyzer)

Model: SPECTRAN HF-60105 (including high precision timing base and 15dB low noise preamplifier)

Frequency range: 1MHz 9.4GHz (see option can be extended to 9KHz-9.4GHz)

Display average noise level: -155dBm (1Hz); (-170dBm (1Hz) 15dB preamplifier on)

Resolution bandwidth: 200Hz - 50MHz

EMC filter: 200Hz, 9kHz, 120kHz, 200kHz, 1,5MHz, 5MHz

Measurement accuracy: +/- 1dB

Data logger: 64K (Option 001 can be expanded to 1MB)

2) Far field antenna: double cone antenna

Model: BicoLOG 20100E

Frequency range: 20MHz-1GHz

Antenna coefficient factor see detailed specification parameters

Maximum transmit power: 1W (30dBm or 0dbW)

Impedance: 50 Ohms

Gain: -38dBi to 1dB

Antenna factor: 17-34dB/m

3) Far field directional antenna: logarithmic period antenna

Model: HyperLOG60100

Frequency range: 680MHz-10GHz

Antenna coefficient factor see detailed specification parameters

Maximum transmission power: 100W CW (400MHz)

Impedance: 50 Ohms

Standing wave ratio: 1:2.5

Gain: 5dBi

Antenna factor: 22-46dB/m

4) Near Field Antenna: Near Field Probe Set

Model: PSB2 (including UBBV2 preamplifier 1MHz-10GHz)

Frequency range: DC-6 GHz, 4 magnetic field probes, 1 electric field probe

Impedance: 50 Ohm

Preamplifier: UBBV2 (40dB, DC – 8 GHz)

Preamplifier noise figure: 3.5dB (typical)

5) Host: Electromagnetic compatibility test spectrum analyzer (electromagnetic radiation test spectrum analyzer)

Model: SPECTRAN NF-5035

Frequency range: 1Hz to 1MHz (option can be extended to 20 or 30MHz)

Magnetic field measurement range (Tesla): 1pT to 2mT (typical)

Magnetic field measurement range (Gauss): 10nG to 20G (typical) (009 option)

Electric field measurement range: 0.1V/m to 20kV/m (typical)

Resolution Bandwidth (RBW): 0.3Hz to 1MHz (1-3-10 step)

Accuracy: 3% (typical)

5. Anoni electromagnetic compatibility and electromagnetic interference EMC&EMI far field test and near field test application

During the EMC test of products, there are often some problems to solve the electromagnetic interference. The most important thing is to judge the source of the interference. Only after accurately locating the interference source can the symptomatic measures to solve the electromagnetic interference be proposed. In the electromagnetic compatibility compliance pre-test, the radiation leakage test is carried out using various standard EMC antennas of the German Anoni, and the far field measurement is generally used. The standard far-field radiation leakage measurement can tell us quantitatively whether the tested equipment meets the national or international EMC standards, whether there is electromagnetic radiation disturbance exceeding the national or international EMC standards, what is the frequency of electromagnetic interference, and what is the radiation intensity? . For example, the test spectrum is shown below:

After far field measurement, it may still be impossible to tell the engineer where the serious electromagnetic radiation problem comes from! From the connection cable? Switching power supply? Communication Interface? Still from the PCB board? At this point we can use the AARONIA spectrum analyzer with the near-field test of the near-field probe to locate the exact source of the electromagnetic radiation. In order to quickly complete the positioning of the interference source, AARONIA has introduced a near-field probe set with a frequency coverage of DC-9GHz. The probe set includes 4 magnetic field probes and 1 electric field probe, providing comprehensive sensitivity and The best choice of resolution, can be used for the detection and location of electromagnetic interference sources, helping engineers to quickly and easily analyze various electromagnetic interference (EMI) problems. If the test engineer needs more sensitivity, AARONIA also offers an external preamplifier (Pre-amplifier) ​​that can be used with the near-field probe set to provide nearly flat 40dB gain with typical noise figure. Only 3.5dB.

Aaronia's latest SPECTRAN V4 series of spectrum analyzers typically have a sensitivity of -170dBm (1Hz). Using high-performance DSP, real-time display of all test and analysis calculations can detect the frequency and signal strength of surrounding electromagnetic radiation sources, automate spectrum analysis and complex safety limit calculations, and enrich the spectrum software functions. Very expensive and complicated equipment can be completed. The AARONIA SPECTRAN V4 series of spectrum analyzers with EMC antennas, near-field probe sets and external preamplifiers provide excellent performance, fast installation, light weight, wide frequency range, and good resolution and sensitivity. Together with the professionally equipped MCS spectrum analysis software, it provides a cost-effective EMI pre-compliance test analysis tool for engineers to quickly analyze and find EMI interference sources.

Sixth, EMC & EMI electromagnetic compatibility radiation disturbance pre-test typical case

1, car navigation instrument radiation disturbance electromagnetic compatibility pre-test

Electromagnetic compatibility refers to the ability of a device or system to function properly in its electromagnetic environment without posing unacceptable electromagnetic disturbances to anything in its environment. For example, while the car navigation device is convenient for the majority of users, everyone is paying more and more attention to its radiation harassment problem. If the radiation disturbance seriously exceeds the relevant international or national standards (GB 9254-2008 "Radio Disturbance Limits and Measurement Methods for Information Technology Equipment" (EN55022), it will not only affect the normal operation of the interior system, but also may lead to traffic accidents. Endanger the lives of people in the car.

Radiated disturbances in car navigation products include broadband nuisance and narrowband harassment. The DC/DC converter in the car navigation system works in a pulse state, which itself generates strong broadband interference. The speed of the main control chip of the in-vehicle electronic products is constantly increasing, and the ringing of the rising edge of the clock generates rich harmonic narrow-band interference. For the rectification of the radiation disturbance of these car navigation devices, it is necessary to accurately locate the electromagnetic radiation interference, in order to solve the problem. According to the different characteristics of the interference source and the transmission path, the countermeasures such as shielding, filtering and grounding are applied to suppress the electromagnetic radiation disturbance. . At this time, using the AARONIA SPECTRAN spectrum analyzer and its near-field probe for near-field diagnosis, the interference source of electromagnetic radiation in the car navigation system can be accurately found.

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