1、Designation: D4935 10D4935 18Standard Test Method forMeasuring the Electromagnetic Shielding Effectiveness ofPlanar Materials1This standard is issued under the fixed designation D4935; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision
2、, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method provides a procedure for measuring the electromagnetic (EM) shielding effectiveness (SE
3、) of a planarmaterial for a plane, far-field EM wave. From the measured data, near-field SE values maycan be calculated for magnetic (H)sources for electrically thin specimens.2,3 Electric (E) field SE values mayare also able to be calculated from this same far-fielddata, but their validity and appl
4、icability have not been established.1.2 The measurement method is valid over a frequency range of 30 MHz to 1.5 GHz. These limits are not exact, but are basedon decreasing displacement current as a result of decreased capacitive coupling at lower frequencies and on overmoding (excitationof modes oth
5、er than the transverse electromagnetic mode (TEM) at higher frequencies for the size of specimen holder describedin this test method.Any Select any number of discrete frequencies may be selected within this range. For electrically thin, isotropicmaterials with frequency independent electrical proper
6、ties of conductivity, permittivity, and permeability, measurements may willpossibly be needed at only a few frequencies as the far-field SE values will be independent of frequency. If the material is notelectrically thin or if any of the parameters vary with frequency, measurements should be made at
7、 manymake measurements atseveral frequencies within the band of interest.1.3 This test method is not applicable to cables or connectors.1.4 UnitsThe values stated in SI units are to be regarded as standard. No other units of measurement are included in thisstandard.1.5 This standard does not purport
8、 to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use.1.6 This international
9、 standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2.
10、 Referenced Documents2.1 ASTM Standards:4D1711 Terminology Relating to Electrical Insulation3. Terminology3.1 DefinitionsFor definitions of terms used in this test method, refer to Terminology D1711.3.2 Definitions of Terms Specific to This Standard:3.2.1 dynamic range (DR), ndifference between the
11、maximum and minimum signals measurable by the system.3.2.1.1 Discussion1 This test method is under the jurisdiction of ASTM Committee D09 on Electrical and Electronic Insulating Materials and is the direct responsibility of SubcommitteeD09.12 on Electrical Tests.Current edition approved May 1, 2010M
12、ay 1, 2018. Published June 2010May 2018. Originally approved in 1989. Last previous edition approved in 19992010 asD 493599.D4935 10. DOI: 10.1520/D493510.10.1520/D4935-18.2 Wilson, P. F., and Ma, M. T., “A Study of Techniques for Measuring the Electromagnetic Shielding Effectiveness of Materials,”
13、NBS Technical Note 1095, May 1986.3 Adams, J. W., and Vanzura, E. J., “Shielding Effectiveness Measurements of Plastics,” NBSIR 85-3035, January 1986.4 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Stand
14、ardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible
15、to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Co
16、nshohocken, PA 19428-2959. United States1Measurement of materials with good SE require extra care to avoid contamination of extremely low power or voltage values byunwanted signals from leakage paths.3.2.2 electrically thin, adjthickness of the specimen is much smaller (filename for conversion to in
17、put data for spreadsheetand graphing programs.X2.6 The computer program is shown in Fig. X2.1.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned inthis standard. Users of this standard are expressly advised that determinat
18、ion of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withd
19、rawn.Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your
20、comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single
21、 or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 1811FIG. X2.1 ASCII Source Code for Fortran Compiler to GenerateProgram for Calculating Near-field SE Values From MeasuredFar-field SE ValuesD4935 1812
