1、 AEROSPACE RECOMMENDED PRACTICE Alternative (Ecological) Method for Measuring Electronic Product Immunity to External Electromagnetic Fields Issued 2003-07 ARP5889 INTRODUCTION At present, there are some standards such as SAE ARP1972, IEC 61000-4, CISPR Publication 24, etc. that regulate methods for
2、 measuring the immunity of radio and electronic products to external electromagnetic fields. The same idea is in the basis of these methods: generation of an electromagnetic field of a given strength, using a generator and radiating equipment (antenna, TEM-cell, etc.), within some volume where the e
3、quipment under test is placed. The immunity of the product to external electromagnetic fields is evaluated on the product response to the effect generated. The methods defined in these standards have an inherent shortcoming: to realize them, the anechoic chambers (very often of large volume) or the
4、open test sites (polygons) that are specially equipped and organized in special areas. Also, the powerful generating equipment and radiating systems are required. The method described herein is an alternative to these methods. It can be practically considered ecological, as its utilization needs no
5、powerful radiating systems and generation equipment. In addition, this method can be easily utilized outside anechoic chambers. SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is ent
6、irely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefrom, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invi
7、tes your written comments and suggestions. Copyright 2008 SAE International All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior w
8、ritten permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: 724-776-4970 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org Reaffirmed 2008-08SAE ARP5889 - 2 - TABLE OF CONTENTS 1. SCOPE 3 2. NORMATIVE REFERENCES 4
9、 3. DEFINITIONS 4 4. GENERAL4 4.1 Definition of the Currents Induced and the Equipment-Under-Test Immunity6 4.2 Definition of the Voltages Induced and the Equipment-Under-Test Immunity .7 4.3 Definition of the Potentially “Weak“ Points of the Product Design .9 5. MEASURING SET-UP, DEVICES AND EQUIPM
10、ENT.10 5.1 Radio Frequency Generator.10 5.2 Test Effect Transmission Line11 5.3 Injector .11 5.4 Antenna13 5.5 Antenna Output Signal Transmission Line.13 5.6 Measuring Device 13 6. TEST METHODS.136.1 Test Conditions 136.2 Test Procedure.14APPENDIX A THEORETICAL BASIS OF AN ALTERNATIVE (ECOLOGICAL) M
11、ETHOD FOR MEASURING ELECTRONIC PRODUCT IMMUNITY TO EXTERNAL ELECTROMAGNETIC FIELDS .16 APPENDIX B CALIBRATION OF TRANSMISSION LINES TETL AND AOSTL.21 SAE ARP5889 - 3 - 1. SCOPE: This method is used to define the immunity of electric and electronic apparatus and equipment (products) to radiated elect
12、romagnetic (EM) energy. This method is based on injecting the calibrated radio frequency currents (voltages) into external conductors and/or internal circuits of the product under test, measuring the strength of the EM field generated by this product and evaluating its immunity to the external EM fi
13、eld on the basis of the data obtained. The method can be utilized only when it is physically possible to connect the injector to the conductors and/or circuits mentioned before. The method allows: Evaluating immunity of the product under test to external EM fields of the strength equal to a normaliz
14、ed one; Calculating the level of external EM field strength at which the given (including maximum permissible) induced currents or voltages are generated in the equipment under test, or solving the “opposite” task; Finding potentially “weak” points of the product design (housing, shield, etc.), thro
15、ugh which EM energy can enter inside the product. The method capabilities mentioned above define the sphere of its application: Measurements of electronic product immunity to external EM fields at different conditions (polygons, laboratories, in-situ) as an alternative to direct test methods; Operat
16、ing instruments for a designer working out the product of a given immunity to external EM fields. This method cant be directly applied to evaluate the immunity of the equipment under test to the pulse electromagnetic fields. But it can be used to get the initial data necessary to solve this task. SA
17、E ARP5889 - 4 - 2. NORMATIVE REFERENCES: The text of this document includes references to the following normative documents: SAE ARP1972 Procedure of immunity measurement IEC 60050-161:1990 International Electrotechnical Vocabulary Chapter 161: Electromagnetic compatibility IEC 61000-4-3: 1995 Elect
18、romagnetic compatibility (EMC) Part 4: Test and measurement technology Clause 3: Tests on immunity to radiated EM field Amendment A1 to IEC 61000-4-3:1998 3. DEFINITIONS: The terms and definitions defined in IEC 61050-161 are used in this document. 4. GENERAL: Electromagnetic emissions generated whi
19、le operating stationary radio transmitting equipment, handheld radio stations, RF devices, industrial electric equipment and other sources affect the conductors connected to electronic products and internal electric circuits. Therefore the necessity to evaluate their immunity to such effects appears
20、. The direct method of evaluation of the electronic product immunity to the external electromagnetic fields is the following. Using a generator and radiating equipment, the radio frequency field of the given strength is generated. The equipment under test is placed into this field. The products resp
21、onse to the RF field is defined by objective (measuring the induced currents and voltages) or subjective methods. This product response served for evaluation of the product immunity to the external effect of the given level. To realize the direct evaluation method the special polygons, where electro
22、magnetic fields of high strength can be generated, or anechoic chambers are required. Moreover, powerful generating and radiating equipment is required. Therefore the expense to carry out the direct evaluation methods are essential, and only specialized test centers can afford such tests. The sugges
23、ted method for the evaluation of electronic product immunity to the external RF field is the alternative method towards the direct one. SAE ARP5889 - 5 - 4. (Continued): The essence of this method is that the product under test is not exposed in the external electromagnetic field. The product itself
24、 under the influence of the exciting signal generates the relatively low electromagnetic field. The product immunity to the external electromagnetic field which level is defined in the direct method is evaluated on the basis of this exciting signal and the level of the field generated. According to
25、this alternative method, the calibrated low-level signals are injected into the accessible external product conductors and/or its internal circuits. The level of this field is measured using a small antenna and measuring receiver. Using this data for the given (in the direct method) electromagnetic
26、field level, the current and/or voltage induced while such effects are calculated and also the opposite operation (definition of the effect level that generates the given current and/or voltage) is solved. The reciprocal theorem is the theoretical basis of the alternative method. This theorem is cor
27、rect not only for the usual quadrapole, but for the case when the input circuit of the measuring receiver is the output ports of the quadrapole, and the circuit where the current and/or voltage is injected is the quadrapole input circuit. The connection between input and output ports is provided by
28、electromagnetic fields and the parameters of the medium between the mentioned ports can change arbitrarily from point to point. To realize the alternative method of evaluation of electronic product immunity to the external RF field, a low-noise generator, a measuring receiver and a small antenna are
29、 required. At this, the tests can be satisfied not only in the anechoic chamber or at the polygon, but also at the open test site and in the laboratory. These advantages made the alternative method easy to use. In addition, it can be a working instrument for a designer of electronic products. The th
30、eoretical basis for the measuring method defined in this document and the formula derivation are described in Appendix A. According to this method the immunity of electronic products to the external RF EM fields is measured as follows: 1. If e.m.f. U0is injected into any circuit of the equipment und
31、er test then the current I that will be induced by the external electromagnetic field in the same circuit is calculated. 2. If the current I0is injected into any circuit of the equipment under test then the voltage U that will be induced by the external electromagnetic field in the same circuit is c
32、alculated. SAE ARP5889 - 6 - 4.1 Definition of the Currents Induced and the Equipment-Under-Test Immunity: The evaluation of the current I that will be induced by the external electromagnetic field in any circuit is satisfied as follows: a. A calibrated sine-wave voltage of a proper (low) amplitude
33、U0at the frequency F is injected into one of the conductors connected to the equipment under test or into one of its electric circuits; b. Using an antenna and a measuring device, the EM field strength generated by the equipment under test into the external environment is measured over each of the e
34、quipment coordinate surfaces. Maximum value Em maxand also maximum voltage at the input of the measuring receiver U0 maxor maximum current I0 maxat the input circuit of the measuring receiver (input impedance Rin) are defined (Uo max= I0 maxRin).If a dipole is used as the measuring antenna the measu
35、rement are made for both horizontal and vertical antenna polarization. Then, using the data received (Em max, U0 maxor I0 max), the necessary calculations for the product circuit where the e.m.f. U0was injected are made.4.1.1 Evaluation of the Equipment-Under-Test Immunity to the External Electromag
36、netic Field of a Given Strength: The evaluation of the product-under-test immunity at the frequency F to the external EM fields of normalized strength Enormis satisfied using the following: If technical documentation on the product to be tested includes permissible values of the current I maxinduced
37、 in the circuit, into which the test effect U0was injected, then the product is considered resistive (having immunity) to external EM fields Enormwhen1max2max0maxmnorminEERUI (Eq.1) where:.1= U0 max/U0 = the height of the measuring antenna used, normalized to about 1 m SAE ARP5889 - 7 - 4.1.2 Evalua
38、tion of the External Electromagnetic Field Strength Causing the Given Current Induced: The level of the external EM field strength E causing a given current I induced in a circuit into which the test effect U0was injected before is defined using the following. If the value I is given, then E is defi
39、ned by the formula: 1max02max=UERIEmin(Eq.2) 4.1.3 Evaluation of the Product-Under-Test Immunity When the Permitted Level of the Induced Current is Not Given for the Equipment Circuit Which e.m.f. U0was Injected into: If the technical documentation on the product to be tested doesnt include the maxi
40、mum value of the current I maxinduced into the conductor connected to the product (or its internal circuit) then the product is considered resistive (possessing immunity) to external EM fields Enormwhen after repeated injection of the voltage max00mnormnormEEUU = (Eq.3) this equipment operates with
41、the given/proper quality. 4.2 Definition of the Voltages Induced and the Equipment-Under-Test Immunity: The evaluation of the voltage U that will be induced by the external electromagnetic field in any circuit is satisfied as follows. a. Calibrated sine-wave current of a proper (low) amplitude I0at
42、the frequency F is injected into one of the conductors connected to the equipment under test or into one of its electric circuits; b. Using an antenna and a measuring device, the EM field strength generated by the equipment under test into the external environment is measured over each of the equipm
43、ent coordinate surfaces. Maximum value Em maxand also maximum voltage at the input of the measuring receiver U0 maxor maximum current I0 maxat the input circuit of the measuring receiver (input impedance Rin) are defined (Uo max= I0 maxRin).If a dipole is used as the measuring antenna, the measureme
44、nts are made both for horizontal and vertical antenna polarization. Then, using the data received (Em max, U0 maxor I0 max), the necessary calculations for the product circuit where the current I0was injected to, are made.SAE ARP5889 - 8 - 4.2.1 Evaluation of the Equipment-Under-Test Immunity to the
45、 External Electromagnetic Fields of the Given Strength: The evaluation of the test product immunity at the frequency F to external EM fields of normalized strength Enormis satisfied using the following:If technical documentation on the product to be tested includes permissible values of the voltage
46、U maxinduced in the circuit into which the test effect I0was injected then the product is considered resistive (having immunity) to external EM field Enormwhen2max2max0maxmnormEEUU (Eq.4) where:.1= I0 max/I04.2.2 Evaluation of the External Electromagnetic Field Strength Causing the Given Voltage Ind
47、uced: The level of the external EM field strength E causing a given voltage U induced in a circuit into which the test effect I0was injected before is defined using the following.If the value U is given, then E is defined by the formula: 2max02max=UEUEm(Eq.5) 4.2.3 Evaluation of the Product-Under-Te
48、st Immunity When the Permitted Level of the Induced Current is Not Given for the Equipment Circuit Which the Current I0was Injected Into: If the technical documentation on the product to be tested doesnt include maximum values of the voltage U maxinduced into the conductor connected to the product (
49、or its internal circuit) then the product is considered resistive (possessing immunity) to external EM field Enormwhen after repeated injection of the current max00mnormnormEEII = (Eq.6) this equipment operates with the given/proper quality. SAE ARP5889 - 9 - 4.2.3 (Continued): NOTE: All steps described in the clause 4 should be satisfied: a. at all frequencies defined in the immunity standard b. for all physically accessible conductors connected to the product (its internal electric circuits) for which the permissible values o
