1、IEEE Std 1302-2008(Revision of IEEE Std 1302-1998) IEEE Guide for the ElectromagneticCharacterization of ConductiveGaskets in the Frequency Range ofDC to 18 GHz IEEE3 Park Avenue New York, NY 10016-5997, USA9 February 2009IEEE Electromagnetic Compatibility SocietySponsored by theStandards Developmen
2、t Committee1302TMIEEE Std 1302-2008 (Revision of IEEE Std 1302-1998) IEEE Guide for the Electromagnetic Characterization of Conductive Gaskets in the Frequency Range of DC to 18 GHz Sponsor Standards Development Committee of the IEEE Electromagnetic Compatibility Society Approved 10 November 2008 IE
3、EE-SA Standards Board Abstract: Information to assist users of gaskets in evaluating gasket measurement techniques to determine which exhibit the properties critical to the intended application, to highlight limitations and sources of error of the competing measurement techniques, and to provide a b
4、asis for comparing the techniques is provided in this guide. Emphasis is placed on those measurement techniques that have been adopted through incorporation into standards, both commercial and military, or that have been used extensively. Keywords: aperture transmission, electromagnetic shielding, E
5、MI gaskets, measurement techniques, reverberation chamber, shielding effectiveness, stirred mode, transfer impedance The Institute of Electrical and Electronics Engineers, Inc. 3 Park Avenue, New York, NY 10016-5997, USA Copyright 2009 by the Institute of Electrical and Electronics Engineers, Inc. A
6、ll rights reserved. Published 9 February 2009. Printed in the United States of America. IEEE is a registered trademark in the U.S. Patent +1 978 750 8400. Permission to photocopy portions of any individual standard for educational classroom use can also be obtained through the Copyright Clearance Ce
7、nter. Introduction This introduction is not part of IEEE Std 1302-2008, IEEE Guide for the Electromagnetic Characterization of Conductive Gaskets in the Frequency Range of DC to 18 GHz. An EMI gasket is a conductive material used to improve the electrical bonding between metallic parts of an electro
8、nic chassis, equipment enclosure, or electromagnetic shield. A wide variety of materials and techniques is used to produce EMI gaskets. The effectiveness of gaskets in the closing of seams and joints is dependent upon the properties of the gasket and the method of installation. Several techniques ar
9、e available to measure the electromagnetic properties of EMI gaskets. Unfortunately, measurement results are often inconsistent between techniques. This guide provides guidance on the use of recognized techniques for the electromagnetic performance characterization of EMI gaskets. It does not recomm
10、end one technique over another. It is recognized that some or all of the “alternative” techniques may, at some time in the future, become widely accepted and practiced. At such time, the guide will be revised to reflect their adoption. It is also recognized that efforts are currently underway to rev
11、ise the measurement techniques currently covered in this guide. These revisions will be included in future updates of this document. The theory of gasket behavior given in this guide is highly simplified and is intended to illustrate primary principles only. For a greater understanding of the electr
12、omagnetic interactions occurring in a gasketed joint, the reader is advised to consult the many excellent mathematical treatments in books and papers available through the IEEE and other technical publishers. Notice to users Laws and regulations Users of these documents should consult all applicable
13、 laws and regulations. Compliance with the provisions of this standard does not imply compliance to any applicable regulatory requirements. Implementers of the standard are responsible for observing or referring to the applicable regulatory requirements. IEEE does not, by the publication of its stan
14、dards, intend to urge action that is not in compliance with applicable laws, and these documents may not be construed as doing so. Copyrights This document is copyrighted by the IEEE. It is made available for a wide variety of both public and private uses. These include both use, by reference, in la
15、ws and regulations, and use in private self-regulation, standardization, and the promotion of engineering practices and methods. By making this document available for use and adoption by public authorities and private users, the IEEE does not waive any rights in copyright to this document. Updating
16、of IEEE documents Users of IEEE standards should be aware that these documents may be superseded at any time by the issuance of new editions or may be amended from time to time through the issuance of amendments, iv Copyright 2009 IEEE. All rights reserved. v Copyright 2009 IEEE. All rights reserved
17、. corrigenda, or errata. An official IEEE document at any point in time consists of the current edition of the document together with any amendments, corrigenda, or errata then in effect. In order to determine whether a given document is the current edition and whether it has been amended through th
18、e issuance of amendments, corrigenda, or errata, visit the IEEE Standards Association web site at http:/ieeexplore.ieee.org/xpl/standards.jsp, or contact the IEEE at the address listed previously. For more information about the IEEE Standards Association or the IEEE standards development process, vi
19、sit the IEEE-SA web site at http:/standards.ieee.org. Errata Errata, if any, for this and all other standards can be accessed at the following URL: http:/standards.ieee.org/reading/ieee/updates/errata/index.html. Users are encouraged to check this URL for errata periodically. Interpretations Current
20、 interpretations can be accessed at the following URL: http:/standards.ieee.org/reading/ieee/interp/ index.html. Patents Attention is called to the possibility that implementation of this guide may require use of subject matter covered by patent rights. By publication of this guide, no position is t
21、aken with respect to the existence or validity of any patent rights in connection therewith. The IEEE is not responsible for identifying Essential Patent Claims for which a license may be required, for conducting inquiries into the legal validity or scope of Patents Claims or determining whether any
22、 licensing terms or conditions provided in connection with submission of a Letter of Assurance, if any, or in any licensing agreements are reasonable or non-discriminatory. Users of this guide are expressly advised that determination of the validity of any patent rights, and the risk of infringement
23、 of such rights, is entirely their own responsibility. Further information may be obtained from the IEEE Standards Association. Participants At the time this guide was completed, the Electromagnetic Characterization of Conductive Gaskets Working Group had the following membership: Johan Catrysse, Ch
24、air Christian Brull Joseph E. Butler, Jr. Chris Cook Johan Deschacht Fumi Enolo Gary Fenical Steve Frierson Harry Fuerhaupter Dave Garagnani Michael O. Hatfield William Hoge Shane Hudak George M. Kunkel Ross Livington Michael Oliver Joe Rowan Robert Welch The following members of the individual ball
25、oting committee voted on this guide. Balloters may have voted for approval, disapproval, or abstention. Jacob Ben Ary David Baron Michael Brown Johan A Catrysse F A Denbrock Carlo Donati Randall Groves Edward Hare David Hess Werner Hoelzl Daniel Hoolihan Sergiu Iordanescu Efthymios Karabetsos Arthur
26、 Light Jon Martens Gary Michel Michael S. Newman Cam Posani John Vergis Barry Wallen When the IEEE-SA Standards Board approved this guide on 10 November 2008, it had the following membership: Robert M. Grow, Chair Thomas Prevost, Vice Chair Steve M. Mills, Past Chair Judith Gorman, Secretary Victor
27、Berman Richard DeBlasio Andy Drozd Mark Epstein Alexander Gelman William Goldbach Arnie Greenspan Ken Hanus Jim Hughes Richard Hulett Young Kyun Kim Joseph L. Koepfinger* John Kulick David J. Law Glenn Parsons Ron Petersen Chuck Powers Narayanan Ramachandran Jon Walter Rosdahl Anne-Marie Sahazizian
28、Malcolm Thaden Howard Wolfman Don Wright *Member Emeritus Also included are the following nonvoting IEEE-SA Standards Board liaisons: Satish K. Aggarwal, NRC Representative Michael Janezic, NIST Representative Lisa Perry IEEE Standards Project Editor Bill Ash IEEE Standards Program Manager, Technica
29、l Program Development vi Copyright 2009 IEEE. All rights reserved. Contents 1. Overview 1 1.1 Background 1 1.2 Scope . 2 1.3 Purpose 2 2. Normative references 3 3. Acronyms and abbreviations clause . 3 4. Factors affecting gasket performance . 4 5. Gasket measurement techniques . 6 6. Standardized g
30、asket measuring techniques. 7 6.1 Transfer impedanceSAE ARP 1705-2006 (Rev. A) 7 6.2 Relative aperture transmission . 10 7. Alternative techniques, derived from standardized methods 13 7.1 General 13 7.2 Effective transmission aperture . 13 7.3 Slot aperture . 14 7.4 (Nested) reverberation chambers
31、. 15 8. Alternative, non-standardized methods 18 8.1 General 18 8.2 Far-field TEM-t fixture 18 8.3 Near-field H-t fixture . 20 8.4 DC resistance measurement . 21 9. Selecting a gasket measurement technique . 21 9.1 General 21 9.2 Measurement reference 21 9.3 Sample configuration . 22 9.4 Frequency r
32、ange 22 9.5 Dynamic range . 23 9.6 Other considerations 24 10. Repeatability and measurement uncertainty . 24 10.1 Repeatability 24 10.2 Measurement uncertainty . 25 vii Copyright 2009 IEEE. All rights reserved. viii Copyright 2009 IEEE. All rights reserved. 11. Test plan . 26 11.1 General 26 11.2 T
33、est plan parameters to be defined 26 11.3 Calibration . 26 11.4 Reference level and dynamic range . 26 12. Technical report 27 12.1 General 27 12.2 Status letter 27 12.3 Full test report 27 Annex A (normative) Summary of measuring techniques for gasket . 29 Annex B (normative) Introduction to the el
34、ectromagnetic behavior of gasketed joints . 31 Annex C (informative) Detailed tabulation of standardized aperture transmission methods . 37 Annex D (informative) Some in-depth discussion on the use of reverberation chambers 40 Annex E (informative) Test methods for on-board gasket applications . 42
35、Annex F (informative) Bibliography 45 IEEE Guide for the Electromagnetic Characterization of Conductive Gaskets in the Frequency Range of DC to 18 GHz IMPORTANT NOTICE: This standard is not intended to assure safety, security, health, or environmental protection in all circumstances. Implementers of
36、 the standard are responsible for determining appropriate safety, security, environmental, and health practices or regulatory requirements. This IEEE document is made available for use subject to important notices and legal disclaimers. These notices and disclaimers appear in all publications contai
37、ning this document and may be found under the heading “Important Notice” or “Important Notices and Disclaimers Concerning IEEE Documents.” They can also be obtained on request from IEEE or viewed at http:/standards.ieee.org/IPR/disclaimers.html. 1. Overview 1.1 Background The ideal electromagnetic s
38、hield is an infinitely conductive enclosure with no apertures or penetrations of any kind. Functional requirements and practicalities of design and construction prevent this ideal from being realized. Penetrations for power, signals, and ventilation must be provided. Access apertures for calibration
39、s, controls, and adjustments must exist. The different pieces of chassis and enclosure must be joined for the final product. Electromagnetic energy exits or enters the shield at apertures, along conductive penetrations, and through imperfect seams. To restrict this coupling of energy to levels suffi
40、ciently low to comply with regulations and to permit interference-free operation, these unwanted coupling paths must be closed. Filters are used on the penetrations; screens and covers may be used over apertures. Seams and joints require special attention, however. For shielding, metal flow processe
41、s such as welding, brazing, and soldering are the preferred methods for making joints and seams. Many situations arise, however, where these techniques cannot be used and direct metal-to-metal contact does not provide an adequate electromagnetic seal. In these cases, an electromagnetic interference
42、(EMI) gasket should be installed in the joint. EMI gaskets are conductive materials designed to conform to joint surfaces and provide a low-impedance path. EMI gaskets are made from a wide variety of materials: beryllium copper, galvanized steel, stainless 1 Copyright 2009 IEEE. All rights reserved.
43、 IEEE Std 1302-2008 IEEE Guide for the Electromagnetic Characterization of Conductive Gaskets in the Frequency Range of DC to 18 GHz steel, electroplated steel, aluminum, and conductively loaded polymers. Gasket types include spring fingers, spiraled bands, perforated sheets, knitted wire mesh, cond
44、uctive fabric, reinforced foil, and oriented wires. Materials added to polymeric binders to achieve conductivity include copper, silver, carbon, aluminum, and nickel as flakes, powders, wires, and coated spheres. The shapes available include sheets, strips, washers, tubes, and customized geometries.
45、 The term “EMI gasket” is consistent with the generic industrial definition of a gasket. The electromagnetic fields being shielded impinge on the conductive materials of the enclosure. The incident field induces currents in the enclosure walls. Seams represent discontinuities in shield current paths
46、 with resulting voltage differentials across the seams. The purpose of the EMI gasket is to reduce the voltage differential across the seam because the strength of the field emanating from the seam is directly proportional to this voltage. Depending upon function and application, electronic equipmen
47、t operates in an extremely wide range of electromagnetic environments (EMEs) in terms of both intensity and frequency. The environments can vary from that of the home to the battlefield. Since there is no “one size/type fits all” gasket, the challenge facing equipment designers is that of choosing t
48、he most efficient and cost-effective gasket for their particular application. An essential parameter in this selection process is the degree to which the gasket prevents electromagnetic energy impinging on one side of the metal joint containing the gasket from coupling through the joint to the other
49、 side (i.e., the gaskets electromagnetic shielding capability). Many factors determine the electromagnetic seal provided by an EMI gasket, including the following: a) Gasket material b) Gasket construction and geometry c) Geometry of the joint d) Condition of the contact surfaces e) Method of fastening f) Closure pressure g) Nature of the impinging field The ideal EMI gasket measurement technique would reveal the full range of effects caused by mounting surface variations, aging, and fasteners and would provide results that indicate the behavior expected from the gasket
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