1、 IEC 61726 Edition 3.0 2015-09 INTERNATIONAL STANDARD Cable assemblies, cables, connectors and passive microwave components Screening attenuation measurement by the reverberation chamber method IEC 61726:2015-09(en) THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2015 IEC, Geneva, Switzerland All
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11、wave components Screening attenuation measurement by the reverberation chamber method INTERNATIONAL ELECTROTECHNICAL COMMISSION ICS 33.120.10; 33.120.30 ISBN 978-2-8322-2893-7 Registered trademark of the International Electrotechnical Commission Warning! Make sure that you obtained this publication
12、from an authorized distributor. 2 IEC 61726:2015 IEC 2015 CONTENTS FOREWORD . 3 1 Scope 5 2 Normative references . 5 3 Terms and definitions. 5 4 Basic description of the reverberation chamber method 5 5 Measurement of the screening attenuation of the device under test (DUT) 6 6 Description of the t
13、est set-up . 6 6.1 Reverberation chamber . 6 6.2 Mode stirrer 7 6.3 Antennas. 7 6.4 Test equipment . 7 6.5 Device under test (DUT) 7 6.6 Linking devices . 8 7 Measurement procedure 8 7.1 General . 8 7.2 Measurement of the DUT 9 7.2.1 General . 9 7.2.2 Standard measurement 9 7.2.3 Fast measurement .
14、9 7.3 Measurement of the insertion loss of the cavity 10 7.4 Control of the test set-up . 10 7.4.1 Dynamic range . 10 7.4.2 Insertion loss of the chamber . 11 7.4.3 Measurement of a calibrator . 11 7.4.4 Measurement of lossy DUT 11 7.5 Revolution speed of the mode stirrer . 11 7.6 Test frequencies .
15、 11 7.7 Voltage standing wave ratio (VSWR) . 12 8 Evaluation of the test results 12 Annex A (informative) Relationship between transfer impedance and screening attenuation 13 Annex B (informative) Example of a calibrator 14 Bibliography 16 Figure 1 Example of a test set-up . 7 Figure B.1 Basic const
16、ruction details 14 IEC 61726:2015 IEC 2015 3 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ CABLE ASSEMBLIES, CABLES, CONNECTORS AND PASSIVE MICROWAVE COMPONENTS SCREENING ATTENUATION MEASUREMENT BY THE REVERBERATION CHAMBER METHOD FOREWORD 1) The International Electrotechnical Commission (IEC) is a wo
17、rldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in addition to other
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26、 Publications. 8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is indispensable for the correct application of this publication. 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subje
27、ct of patent rights. IEC shall not be held responsible for identifying any or all such patent rights. International Standard IEC 61726 has been prepared by IEC technical committee 46: Cables, wires, waveguides, R.F. connectors, R.F. and microwave passive components and accessories. This third editio
28、n cancels and replaces the second edition, published in 1999. This edition constitutes a technical revision. It takes into account the latest developments in the design of reverberation chambers as described in IEC 61000-4-21, which is also referencing this standard as a possible test method. Furthe
29、rmore, an alternative measurement procedure is added which is able to reduce the measurement time needed. 4 IEC 61726:2015 IEC 2015 The text of this standard is based on the following documents: FDIS Report on voting 46/551/FDIS 46/569/RVD Full information on the voting for the approval of this stan
30、dard can be found in the report on voting indicated in the above table. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. The committee has decided that the contents of this publication will remain unchanged until the stability date indicated on the IEC web site un
31、der “http:/webstore.iec.ch“ in the data related to the specific publication. At this date, the publication will be reconfirmed, withdrawn, replaced by a revised edition, or amended. A bilingual version of this publication may be issued at a later date. IEC 61726:2015 IEC 2015 5 CABLE ASSEMBLIES, CAB
32、LES, CONNECTORS AND PASSIVE MICROWAVE COMPONENTS SCREENING ATTENUATION MEASUREMENT BY THE REVERBERATION CHAMBER METHOD 1 Scope The requirements of modern electronic equipment have indicated a demand for a method for testing screening attenuation of microwave components over their whole frequency ran
33、ge. Convenient test methods exist for low frequencies and components of regular shape. These test methods are described in the relevant IEC product specifications (e.g. IEC 62153-4-3). For higher frequencies and for components of irregular shape, a new test method has become necessary and such a tes
34、t method is described in this International Standard. This International Standard describes the measurement of screening attenuation by the reverberation chamber test method, sometimes named mode stirred chamber, suitable for virtually any type of microwave component and having no theoretical upper
35、frequency limit. It is only limited toward low frequencies due to the size of the test equipment, which is frequency- dependent and is only one of several methods of measuring screening attenuation. For the purpose of this standard, examples of microwave components are waveguides, phase shifters, di
36、plexers/multiplexers, power dividers/combiners etc. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edi
37、tion of the referenced document (including any amendments) applies. IEC 61196-1, Coaxial communication cables Part 1: Generic specification General, definitions and requirements IEC TS 62153-4-1, Metallic communication cable test methods Part 4-1: Electromagnetic compatibility (EMC) Introduction to
38、electromagnetic screening measurements IEC 61000-4-21, Electromagnetic compatibility (EMC) Part 4-21: Testing and measurement techniques Reverberation chamber test methods 3 Terms and definitions For the purposes of this document, the terms and definitions given in IEC 61196-1 and IEC 61000-4-21 app
39、ly. 4 Basic description of the reverberation chamber method The reverberation chamber method for measurement of the screening attenuation of microwave components consists of exposing the device under test (DUT) to an almost homogeneous and isotropic electromagnetic field and then measuring the signa
40、l level induced into the device. 6 IEC 61726:2015 IEC 2015 These conditions are achieved by the use of a shielded enclosure, which acts as an oversized cavity (in terms of wavelength), with a high quality factor. Its boundary conditions are continuously agitated by a rotating reflective surface (mod
41、e stirrer), mounted within the chamber, which enables the field to approach homogeneous and isotropic conditions during one revolution. Electromagnetic power is fed to the chamber by means of an input or transmitting antenna. The strength of the field inside the chamber is measured through a referen
42、ce antenna. The ratio of the injected power (input antenna) to the received power (reference antenna) is the insertion loss of the cavity. The insertion loss is strongly frequency dependent and is also dependent on the quality factor of the cavity. More detailed explanation on the measurement facili
43、ty can be found in IEC 61000-4-21. It has been shown that, due to the isotropic field, any antenna placed inside the cavity behaves as if its gain was unity 2 1 , therefore no directional effect is to be expected. If the device under test is electrically short, its screening attenuation will be dire
44、ctly related to usual transfer parameters (Z tand Z f ). If the device under test is not electrically short, the screening attenuation may still be related to Z tand Z fin some simple cases (evenly distributed leakage, periodically distributed leakage) using summing functions derived from antenna ne
45、twork theory. 5 Measurement of the screening attenuation of the device under test (DUT) The measurement of screening attenuation is based on the comparison of the electromagnetic field power outside the DUT to the electromagnetic field power induced into the DUT. The screening attenuation is then de
46、fined as: = REF DUT 10 s log 10 P P a (1) or ins INJ DUT 10 s log 10 D = P P a(2) where P DUTis the power coupled to the device under test (W); P REFis the power coupled to the reference antenna (W); P INJis the power injected into the chamber (W); D insis the insertion loss of the chamber in decibe
47、ls (dB). 6 Description of the test set-up 6.1 Reverberation chamber The used reverberation chamber shall be compliant to IEC 61000-4-21. In general, a reverberation chamber is a shielded enclosure having any shape. A perfect cubic shape should be avoided for optimum performance at lower frequencies.
48、 It shall be made of conductive materials (copper, aluminium or steel) and shall not contain lossy materials. The size of the cavity depends on the lowest test frequency. For a sufficient test facility, a number of at least 100 modes need to be present at this frequency. The upper frequency limit de
49、pends _ 1 Figures in square brackets refer to the Bibliography. IEC 61726:2015 IEC 2015 7 on the quality of the shielding enclosure and cables. Furthermore, the sensitivity of the used measurement instruments limits the maximum useable frequency. 6.2 Mode stirrer The mode stirrer shall be large with respect to wavelength and be bent at angles to the walls of the chamber. The mode stirrer shall be at least two wavelengths from tip to tip at the lowest test
