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NGUYEN DUC TRUONG RESEARCH SOLUTIONS TO ASSESS AND ENSURE ELECTROMAGNETIC COMPATIBILITY FOR ELECTRONIC RADIO DEVICES Specialization: Radio and Electronic Physics Code: 44 01 05 SUMMARY OF PHYSICS DOCTORAL THESIS Hanoi - 2020 This Thesis was completed at: Academy of Military Science and Technology Academic Supervisors: Assoc Prof Dr Ho Quang Quy Assoc Prof Dr Bui Van Sang Reviewer 1: Assoc Prof Dr Nguyen Quang Hung Reviewer 2: Assoc Prof Dr Do Trong Tuan Reviewer 3: Dr Ta Chi Hieu This thesis will be defended in front of Doctor Examining E valuating Committee held at Academy of Military Science and Technology at … … , ……………………2020 This thesis can be found at: - The Library of Academy of Military Science and Technology - The Vietnam National Library INTRODUCTION The Urgency: Today the EMC (Electromagnetic Compatibility) has quickly played an important role in of circuit analysis and electronics engineering The rapid growth is due to the increasing use of electronic devices, in addition to which most countries around the world have set limits on radiation and transmission noise of products, electronic products The presence of interference caused by electrical and electronic equipment can reduce the performance of themselves and surrounding devices, especially in military equipment such as submarines and warships, fighter planes, etc., where system space is very limited, but the number of electrical and electronic devices can be very large and operate simultaneously Therefore, ensuring electromagnetic compatibility (Electromagnetic Compatibility-EMC) for electronic radio equipment (VTDT) is a very urgent issue This area of science needs more attention due to the sharp increase in the number and scale of electrical and electronic devices Therefore, I have chosen the topic "Research solutions to assess and ensure electromagnetic compatibility for electronic radio devices" with the following objectives and contents as follows: The objective: Research and complete evaluation solutions, ensuring EMC when designing and manufacturing radio devices based on electromagnetic shielding and estimating the distance of functional blocks; study the EMC influence of the nearest noise source and the total noise power in the radio system to determine a simple and appropriate evaluation method The object: The thesis goes into research, analyzes evaluation solutions, ensures EMC for blocks in radio equipment, assesses the impact of the nearest source of interference on radio equipment and radio systems are currently in common use The scope: Research on EMC theory, analyze the methods applied currently in the system and devices VTDT on domestic and foreign telecom devices, from which proposing complete solutions New improvement in both theory and practice Study of EMC in a specific telecom system or device VTDT, find out the electromagnetic relationships and interactions between devices in a system and between functional blocks in a separate electronic device, simulate research results by software and draw conclusions Research content: Research solutions to ensure electromagnetic compatibility for electronic devices VTDT, focusing on electromagnetic shielding method and distance estimation The study evaluates the probability of interrupting the operation of radio systems under the action of the nearest source of disturbance replacing the effect of total disturbance power Research methodology: Research methodology is based on collecting information, documents, general analysis of scientific works and articles published in the world and in the country, applying them Radio wave theory, electromagnetic field theory, statistical probability and calculus calculus to build mathematical relationships between elements and the entire system Evaluate results using CST and MonteCarlo simulation software on computers and test on hardware Scientific and practical significance: The remarks and conclusions of the thesis are given on the basis of mathematical analysis, verified by experiment and simulation, ensuring reliability, contributing to perfecting the method of ensuring EMC for telecom equipment VTDT The method of electromagnetic shielding and the estimation of the distance of blocks with recommendations drawn from experiment and simulation help in the design and manufacture of telecom equipment The method of evaluating the probability of interruption of the operation of the telecom system under the impact of the nearest interference source replacing the effect of the total interference power contributes to simplifying the method of ensuring EMC for telecom equipment These are two contents with new and scientific significance The results of calculation, experiment and verification simulation in the thesis contribute to perfecting the method of ensuring EMC for telecom equipment From these results, it helps design and manufacture of new telecom devices to achieve and comply with EMC standards, improve the reliability of the equipment Structure of the thesis: In addition to the introduction, conclusion, list of published works of the thesis, references and appendices, the content of the thesis consists of chapters: Chapter General review of EMC assessment and assurance solutions for radio devices; Chapter Proposing solutions to ensure EMC when designing electronic telecommunication equipment; Chapter Proposal solution to assess the nearest noise source instead of the total noise power Chapter OVERVIEW OF EMC ASSURANCE AND ASSESSMENT SOLUTIONS FOR RADIO DEVICES 1.1 Concepts and EMC characteristics of radio equipment 1.1.1 General concept Electromagnetic compatibility is the ability of a device (electricity, electronics, radio) to operate stably and to ensure parameters in a specific electromagnetic environment and not to produce noise that exceeds the standards specified for other devices [51] 1.1.2 EMC characteristic of radio equipment When dealing with EMC electromagnetic compatibility issues of radio equipment, there are many parameters and characteristics of radio receivers (MT), radio transmitters (MF) and antennas used used to evaluate EMC These characteristics and parameters describe certain properties of the aforementioned devices, derived from the perspective of electromagnetic interference and their ability to prevent them Specifically, within the scope of the thesis, the following content can be considered among the characteristics of EMC [4], [5], [51] 1.2 Some solutions to ensure EMC for radio equipment In order to ensure EMC for radio components, blocks and devices, many solutions have been implemented and yielded certain results The basic methods for limiting or eliminating the effects of interference in equipment circuits are: needle shielding, earthing, filtering, balancing, isolation, distribution and orientation of conductors in the space adjust the circuit impedance [4], [51] Figures 1.7, 1.8 and 1.9 show methods for limiting noise in electrical circuits 1.2.1 Electromagnetic shielding solution As electronic radio equipment became more complex, the requirement to reduce the effects of interference became even more necessary One of the most commonly used methods applied to blocks or the entire electronic device is electromagnetic shielding using metal boxes [6] Electromagnetic shielding is a very useful and common solution to ensure EMC for all components and devices Figure 1.10 The effect of electromagnetic shielding The shielding effect (SE [dB]) of a needle cover can be expressed as a sum of the reflectances (R [dB]), the absorption (A [dB]) and the multiple reflections (B [dB]) as follows [48]: SE [dB] = R [dB] + A [dB] + B [dB] (1.8) 1.2.2 Distance estimation solution Another method used is to estimate the distance between components of an electronic device This method is based on the principle that when an electromagnetic wave propagates through space, the signal strength decreases with distance [47] Figure 1.12 Distance inverse method E ( R' )[dB] E ( R)[dB] 20lg( R ) R' (1.10) 1.2.3 Other solutions 1.3 Models for evaluating the maximum power of noise 1.3.1 Statistical model of maximum power of noise In mobile phone networks, receivers (MT) and transmitters (MPs) are often used in two types: mobile stations (MS) and base stations (BS), forming the basic types of transportation for these two types In [4] surveying models, Figure 1.20 is the typical model we choose for analysis MP(MS) MT(BS) r Rc D MS BS MP(BS)j MT(MS)j Figure 1.20 Statistical model 1.3.2 Some other evaluation models 1.4 Comments and discussions on EMC solutions for electronic radio Electromagnetic compatibility is really interested in countries in the 1970 - 1980 of the 20th century Since the 1980 year, countries such as the US, the former Soviet Union, Japan, have built EMC standards when using electromagnetic resources such as frequency spectrum, electronic components layout density, receiver sensitivity, generator capacity, Currently, our country has only a few EMC electromagnetic compatibility measuring rooms at some key agencies such as: Radio Frequency Department /Ministry of Information and Communications; National Metrology Institute (VMI)/General Department of Finance, Administration, Ministry of Science and Technology; Bureau of Standards - Metrology - Quality/BTTM/BQP Currently, some universities such as Hanoi University of Science and Technology, Posts and Telecommunications Institute, Danang University have a number of topics related to EMC research such as frequency planning, electromagnetic radiation disturbance measurement from elements of receiver, transmitter, antenna - phide, etc For example, at the University of Danang, Dr Tang Tan Chien has had ministerial-level researches "Studying to build a grafting model to expand the bandwidth of TEM cells ”2016 [2]; "Simulation of electromagnetic field transmission by TLM method" in 2002 [3] However, it can be affirmed that until now, there are still a lot of studies on EMC for specific elements, function blocks, electronic devices and telecommunication system, and there is a lack of domestic research on solutions, the evaluation model and EMC criteria for elements, blocks and electronic telecommunication devices can ensure EMC when designing and manufacturing radio equipment and networks, especially in the military field 1.5 The problem of building a solution to assess and ensure electromagnetic compatibility for radio devices 1.5.1 Set the problem With the above analysis, the problem posed and solved in the thesis is: Research, propose solutions to assess and ensure electromagnetic compatibility for electronic radio devices Experimental simulation of computer statistics and hardware testing based on EMC characteristics of electronic devices to analyze, evaluate research results and propose solutions to ensure EMC 1.5.2 Research object, scope and limits With the above posed problem, the thesis identifies the research object as solutions to ensure EMC of radio devices Therefore, the scope of the thesis will focus on the evaluation method, ensuring EMC for electronic telecommunication equipment From there, propose solutions, models to evaluate and ensure EMC for electronic telecommunication devices according to EMC characteristics based on the input parameters of the equipment 1.5.3 Research methodology, content and solution The problem is solved based on the application of electromagnetic field theory and wave propagation, statistical probability theory and calculus calculus to build mathematical relationships, proposing some solutions in the problem EMC guaranteed price Perform verification, evaluate results by computer simulations and test EMC algorithms on hardware 1.6 Conclusion of chapter Based on the findings of the review in chapter 1, some comments can be drawn as follows: Ensuring EMC electromagnetic compatibility is important for reliable, proper operation of electrical, electronic and constituent components In order for the EMC research content to be effective, it is necessary to have a firm grasp of the design, function of the device, element, and sources of impact Electrical and electronic equipment are diverse in type, structure, function and increasingly innovative in manufacturing technology, so a total solution to ensure EMC for all types of equipment is difficult Feasibility Therefore, research works on EMC that are specific to each specific case are very necessary and topical For the reasons mentioned above, the research direction of the thesis is limited to the following contents: electromagnetic shielding for elements and estimation of distances for blocks in radio equipment, proposing solutions to ensure EMC when design electronic telecommunication equipment, propose mathematical model to evaluate the statistics of electromagnetic interference, in which the nearest noise source is evaluated instead of the total noise power These are new contents to be studied in chapters and of the thesis Chapter PROPOSED SOLUTIONS TO ENSURE EMC WHEN DESIGNING RADIO DEVICES With the EMC research and analysis in chapter 1, the thesis proposes a solution to ensure EMC when designing electronic radio devices based on the application of electromagnetic shielding (needle coating) in combination with method of estimating the distance between blocks, thereby serving as a basis for building a model to ensure EMC when designing radio equipment 2.1 Proposed Solutions 2.1.1 Question The EMC assurance methods mentioned in section 1.2 each have their own advantages and disadvantages The thesis will mention to ensure EMC for electronic equipment with one or more blocks available, ie not interfere with the circuit or block design process Therefore, the thesis proposes a solution combining needle coating method and estimating distance between blocks to improve EMC for electronic radio equipment 2.1.2 Implementation model The problem is carried out with an aluminum-coated first needle box (the reason for choosing materials in section 2.2.1) is 16 cm x 10 cm x cm, the thickness of the shell is mm The radiation source is placed inside the first needle box through a coaxial cable of 50 Ω impedance and copper wire with a diameter of 0,16 cm to ensure uniform istribution of electromagnetic radiation inside the box as shown in Figure 2.1 [31 ] A second needle-wrapped box measuring 10 cm x 10 cm x cm in aluminum is placed at a distance of d from the first needle box Figure 2.1 Needle-wrapped box model 2.2 Analysis of proposed solutions 2.2.1 Solution coated with needles Figure 2.2 Theoretical shielding effect of aluminum alloy box With the needle-coated box selected by the author, the thickness of the needle cover is mm, the material of the needle cover is aluminum r = and r = 0,61 (with frequencies above 500 kHz) [48] The shielding effect of the needle coating method calculated according to (2.1) is shown in Figure 2.2 As can be seen in Figure 2.2, when using an aluminum alloy cover of mm thickness and considering the frequency range of CISPR-22 standard from 30 MHz to GHz [43], the shielding effect is great (more than 1000 dB) 2.2.2 Distance estimation solution In the far field the emission intensity of the radio waves is assumed to be inversely proportional to the distance as (2.7): R ) R' R L dB E R ' dB E R dB 20lg ' R E ( R' )[dB] E ( R)[dB] 20lg( (2.7) (2.8) The attenuation efficiency of the distance estimation solution calculated by the formula (2.8) is shown in Table 2.3 Table 2.1 Theoretical attenuation of the distance estimation solution Distance (cm) Attenuation L (dB) 3,52 6,02 7,96 9,54 10,88 11 2.4 Tested on real circuits After theoretical analysis and simulation, the thesis will perform measurements on real circuits to confirm the effectiveness of the solution combining the needle coating method and estimate the distance on the actual circuit as shown in Figure 2.15 Figure 2.15 Test image on actual circuit (Appendix 2) Figure 2.22 Oscillator and source circuit spaced d (cm) apart without barrier The distance d (cm) is varied to different values of cm, cm, cm, cm, cm, cm, cm, cm and 10 cm The test shows that the effect of the electromagnetic field between the two circuit blocks is most reduced when the two circuits are needle coated and spaced 10 cm apart 12 Figure 2.23 Signal strength in case of the source circuit and the oscillating circuit spaced 10 cm apart, without shielding The obtained results are shown in figure 2.20 (two uncoated and side by side circuits) and in figure 2.24, figure 2.25, (two needle-coated circuits spaced close to each other and spaced 10 cm apart), figure 2.26 (comparison the electromagnetic attenuation of the foil and the uncoated) shows that the attenuation of the electromagnetic signal when applying the proposed solution compared with the case without the EMC guaranteed method is about 25 dB - 30 dB Figure 24 Oscillating circuit and power circuit covered with needle spaced d (cm) 13 Figure 2.25 The case signal strength is set 10 cm apart 2.5 Figure 2.26 Compare the electromagnetic decline when using needle wrap and changing the spacing (data are taken from annex 3) Based on the theoretical results, simulation results and experimental results in the above cases, we can find out the stated EMC assurance solutions such as needle wrap, distance estimation or Combining solutions both work to reduce unwanted electromagnetic signals emitted in electronic equipment Needle-coated solutions or distance estimation have separate advantages and disadvantages, we evaluate each solution and evaluate both solutions at the same time 14 2.5 Proposing solutions to ensure EMC when designing electronic telecommunication equipment Start - Determine functions specifications of TBVT - Affect parameter - EMC limits level btci Adjust schematic diagram and Design schematic diagram of TBVT Adjust schematic diagram Divide blocks according parameter and function Block n Block Block ≤ btci ? No Electromagnetic shielding for each block Yes ≤ btci ? No Adjust distance of components Yes ≤ btci ? Yes Make prototype block Từ tất khối No Make prototype TBVT No Electromagnetic shielding for TBVT ≤ btci ? Another solutions Yes ≤ btci ? No Yes Adjust distance of blocks Another solutions No ≤ btci ? No Yes ≤ btci ? Yes Manufacture TBVT End No ≤ btci ? Yes Figure 2.27 Design flow chart of electronic telecommunication equipment to ensure EMC 2.6 Conclusion of chapter The thesis has implemented a combination solution between the needle coating method and the method of estimating the distance between blocks of radio equipment The author has performed simulation by CST software and tested the actual circuit, the solution's effectiveness contributes significantly to reducing radiation intensity, ensuring proper working function and not disrupting the function of other equipment when using From the experimental results, the thesis proposes a design process to ensure EMC for radio equipment applying technical solutions combining needle coating method and estimation method of distance between blocks of radio equipment electronic 15 Chapter PROPOSED SOLUTIONS FOR ASSESSING THE NEAREST INTEREST SOURCES IN TOTAL CAPACITY Based on the research results in the previous chapters and some methods to assess and ensure EMC for radio devices, chapter will propose the model of statistical evaluation of the nearest interference source and ensure EMC for the electronic radio equipment Experimental statistical simulation on the computer with assumed parameters of evaluation models, ensuring EMC to analyze, evaluate the effectiveness, reliability of the algorithm and make some recommendations and recommendations Visually, we can see that the noise source with the highest power will have the greatest impact on the probability of interruption of operation (as analyzed in section 3.1), so the author of the thesis focused on the analysis The effect of the strongest noise source is that the probability of an interruption in that operation receives a reduced form The results of analysis and simulation can be seen that at the probability of small disruption, the probability of receiving the highest power source and the total noise power is the same (according to the research results in chapter of thesis) Consider a number of point (Tx ) and point (Rx) transponders placed randomly on a limited area of Sm space as a noise model of the physical network wireless network, m = {1, , 3} is the number of spatial dimensions (1-D, 2-D or 3-D) Figure 3.1 Illustration of geographical space S.Small space area (the vicinity of the node), large space area (the space expanded around the node does not overlap) and the cyberspace The probability for more than one transmitter to fall into dS is insignificant, P (k> 1, dS)
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