1、BRITISH STANDARD BSEN 61580-9:1997 IEC 1580-9: 1996 Methods of measurement for waveguides Part 9: Reflection coefficient at retangular waveguide interfaces The European Standard EN 61580-9:1996 has the status of a British Standard ICS 33.120.10BSEN61580-9:1997 This British Standard, having been prep
2、ared under the direction of the Electrotechnical Sector Board, was published under the authority of the Standards Board and comes into effect on 15February 1997 BSI 12-1998 The following BSI references relate to the work on this standard: Committee reference EPL/46/2 Draft for comment 96/203429 DC I
3、SBN 0 580 26941 8 Committees responsible for this British Standard The preparation of this British Standard was entrusted by Technical Committee EPL/46, Cables, wires and waveguides, RF connectors and accessories for communication and signalling, to Subcommittee EPL/46/2, RFconnectors and waveguides
4、, on which the following bodies were represented: AEA Technology BEAMA Electrical Cable and Conductor Accessory Manufacturers British Non-Ferrous Metals Federation British Telecommunications plc Federation of the Electronics Industry Ministry of Defence National Supervisory Inspectorate Society of C
5、able Television Engineers Amendments issued since publication Amd. No. Date CommentsBSEN61580-9:1997 BSI 12-1998 i Contents Page Committees responsible Inside front cover National foreword ii Foreword 2 Text of EN 61580-9 3 List of references Inside back coverBSEN 61580-9:1997 ii BSI 12-1998 Nationa
6、l foreword This British Standard has been prepared by Subcommittee EPL/46/2 and is the English language version of EN 61580-9:1996 Methods of measurement for waveguides Part 9: Reflection coefficient at retangular waveguide interfaces, published by the European Committee for Electrotechnical Standar
7、dization (CENELEC). It is identical with IEC 1580-9:1996 published by the International Electrotechnical Commission (IEC). A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance w
8、ith a British Standard does not of itself confer immunity from legal obligations. Cross-reference Publication referred to Corresponding British Standard IEC 154 series BS EN 60154 Flanges for waveguides Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, th
9、eEN title page, pages 2 to 8, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on theinside front cover.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 61580-9 Augus
10、t 1996 ICS 33.120.10 Descriptors: Waveguides, reflection coefficient at rectangular interfaces English version Methods of measurement for waveguides Part9:Reflection coefficient at rectangular waveguide interfaces (IEC 1580-9:1996) Mthodes de mesure appliques aux guides dondes Partie 9: Coefficient
11、de rflexion aux interfaces de guides dondes rectangulaires (CEI 1580-9:1996) Meverfahren fr Hohlleiter Teil 9: Dmpfungskoeffizient rechteckiger Hohlleiter-Adapter (IEC 1580-9:1996) This European Standard was approved by CENELEC on 1996-07-02. CENELEC members are bound to comply with the CEN/CENELEC
12、Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CENEL
13、EC member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions.
14、CENELEC members are the national electrotechnical committees of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CENELEC European Committee for Electrotechnical Standardizat
15、ion Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B-1050 Brussels 1996 Copyright reserved to CENELEC members Ref. No. EN 61580-9:1996 EEN61580-9:1996 BSI 12-1998 2 Foreword The text of document 46B/210/FDIS,
16、future edition1 of IEC 1580-9, prepared by SC 46B, Waveguides and their accessories, of IEC TC 46, Cables, wires, waveguides, R.F. connectors, and accessories for communication and signalling, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN61580-9 on1996-07-02. The f
17、ollowing dates were fixed: Annexes designated “normative” are part of the body of the standard. In this standard, Annex ZA is normative. Annex ZA has been added by CENELEC. Contents Page Introduction 3 1 Scope 3 2 Normative reference 3 3 List of symbols 3 4 Effect of dimensional changes and axial di
18、splacement 3 5 Angular misalignment between waveguide flanges 5 Annex ZA (normative) Normative references to international publications with their corresponding European publications 8 Figure 1 Illustration of section discontinuities 6 Figure 2 Graphs for determination of reflection coefficient 7 la
19、test date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 1997-04-01 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 1997-04-01EN61580-9:1996 BSI 12-1998 3 Introduction Due
20、 to tolerances in waveguide dimensions, flange alignment holes and bolt diameters, the junction between two similar waveguides can give rise to reflections of an input signal. This part of IEC1580 examines the effects on reflection coefficient due to the various tolerances. 1 Scope This part of IEC1
21、580 gives the means for determining the reflection coefficient at the junction of two similar rectangular waveguides due to the following imperfections: a) differences in the waveguide internal dimensions; b) lateral displacement between the waveguide axes in either the H or E plane; c) angular misa
22、lignment between the waveguide axes. 2 Normative reference The following normative document contains provisions which, through reference in this text, constitute provisions of this part of IEC1580. At the time of publication, the edition indicated was valid. All normative documents are subject to re
23、vision, and parties to agreements based on this part of IEC1580 are encouraged to investigate the possibility of applying the most recent edition of the normative document indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. IEC 154, Flanges for wave
24、guides. 3 List of symbols Let: The above symbols are illustrated in Figure 1. In addition, let: 4 Effect of dimensional changes and axial displacement 4.1 Combination of mismatches For small dimensional changes, r aand r bare due to the resistive mismatches between the waveguides, the shunt suscepta
25、nces being negligible. The reflection coefficients due to displacements, r Hand r E , are due to shunt susceptances and consequently in phase quadrature with (r a + r b ). The total mismatch due to the combination of dimensional changes and axial displacement is therefore: NOTE 1The highest value of
26、 reflection coefficient for axially aligned waveguides is when a and b are at extreme tolerances and awaveguide with dimensions (a + D a ), (b D b ) mates with a waveguide with dimensions (a D a ), (b + D b ). NOTE 2r Hand r Ehave opposite signs, r Hbeing due to an inductive susceptance and r Eto a
27、capacitive susceptance. a = basic inside width of the waveguide; b = basic inside height of the waveguide; l g = waveguide wavelength; l c = cut-off wavelength; D a , D b = deviations from the basic internal waveguide dimensions; D a , D b = linear displacements between the waveguide axes. r a = ref
28、lection coefficient due to changes in waveguide width; r b = reflection coefficient due to changes in waveguide height; r H = reflection coefficient due to H-plane displacement; r E = reflection coefficient due to E-plane displacement. (1)EN61580-9:1996 4 BSI 12-1998 4.2 Theoretical considerations I
29、n the IEC 154 series of standards, the following formula is given for the maximum reflection due to the combination of dimensional changes and lateral displacement for rectangular waveguides: where R is the reflection loss. Equation (2) can be re-written in terms of reflection coefficients as follow
30、s: Equation (3a) is identical to equation (1). The separate factors in equation (3a) can be expressed as follows: 4.3 Determination of reflection coefficients These may be determined either by use of equations (4) to (7) or by means of the graphs shown in Figure 2 where the reflection coefficients a
31、re expressed as percentages. For r bthe ordinate of Figure 2 may be used directly as r bis independent of frequency. For r a , r Hand r Ethe ordinate takes into account the frequency of operation. (2) therefore (3) i.e. (3a) (4) (5) (6) (7)r b Db b - =EN61580-9:1996 BSI 12-1998 5 NOTE 1For mid-band
32、operation of a waveguide approximates to unity and the ordinate gives the approximate mid-band values for r aand r H . NOTE 2For waveguides with a 2 : 1 aspect ratioand the ordinate gives the approximate mid-band value of r E . 4.4 Summary Equation (2) has been accepted by the IEC for the determinat
33、ion of reflection loss (i.e.return loss) between two rectangular waveguide flanges in the IEC 154 series of flange standards. These standards contain tables of reflection loss based on the criterion that the maximum allowable displacement between waveguide flanges should not degrade the inherent ret
34、urn loss due to waveguide dimensional tolerances by more than 1dB. This leads to a maximum value for D aof 0,0175a for a waveguide tolerance of a/500. For the larger sizes of waveguide this gives a worst-case value of return loss of approximately 40dB. 5 Angular misalignment between waveguide flange
35、s For a rotation of q between the flanges of two identical rectangular waveguides, with aspect ratios of2:1, the following approximate expression may be used to determine the mid-band value of reflection coefficient: where r tis due to the effect of an inductive susceptance. Equation (8) may be used
36、 for values of q up to 45 but r tvaries with aspect ratio and also varies inversely with frequency. r t= 0,5 sin 2q (8) l c l g l g 4b - l g l c - =EN61580-9:1996 6 BSI 12-1998 Figure 1 Illustration of section discontinuitiesEN61580-9:1996 BSI 12-1998 7 Figure 2 Graphs for determination of reflectio
37、n coefficientEN61580-9:1996 8 BSI 12-1998 Annex ZA (normative) Normative references to international publications with their corresponding European publications This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited
38、 at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition
39、of the publication referred to applies (including amendments). NOTEWhen an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD applies. Publication Year Title EN/HD Year IEC 154 series Flanges for waveguides EN 60154-1 1994 HD 129 seriesBSEN615
40、80-9:1997 BSI 12-1998 List of references See national foreword.BSI 389 Chiswick High Road London W4 4AL | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
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