1、STD-BSI BS EN bL580-7-ENGL 1777 Lb2qbb7 058717b 7OTm BRITISH STANDARD Methods of measurement for waveguides Part 7. Graphical method for the determination of waveguide performance * * m The European Standard EN 61580-7 : 1996 has the status of a British Standard ICs 33.120.10 BS EN 61580-7 : 1997 IE
2、C 1580-7 : 1996 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW STD-BSI BS EN bL580-7-ENGL 1777 = ib2Libb9 0587397 b4T W BS EN 61580-7 : 1997 Committees responsible for this British Standard The preparation of this British Standard was entsusted by Technical Committee EPIJ46,
3、Cables, wires and waveguides, RF connectors and accessories for communication and signalling, to Subcommittee EPL/46/2, RF connectors and waveguides, upon which the following bodies were represented: AEA Technology BEATiW Electrical Cable and Conductor Accessory Manufacturers British Non-Ferrous Met
4、als Federation British Telecommunications plc Federation of the Electsonics Industry Ministry of Defence National Supervisory Inspectorate Sociem of Cable Television Engineerc This British Standard, having been prepared under the direction of the Electrotechnical Sector Board, was published under th
5、e authority of the Standards Board and comes into effect on 15 February 1997 O BSI 1997 Amendments issued since publication Amd*No. IDD EN 61W7 NORME EUROPENNE EUROPrnCEC Nom August 1996 ICs 33.120.10 Descriptors: Waveguides, graphical method for the determination of performance English version Meth
6、ods of measurement for waveguides Part 7 Graphical method for the determination of waveguide performance (IEC 1580-7 : 1996) Mthodes de mesure appliques aux guides dondes Partie 7 Mthode graphique pour dteminer les performances dun guide dondes Mefiverfahen fr Hohlleiter Teil 7 Graphisches Verfahren
7、 zur Bestjrnmung der HohUeiter-eigenschaften (IEC 1580-7 : 1996) (CE1 1580-7 : 1996) This European Standard was approved by CENELEC on 199607-02. CENELEC members are bound to comply with the CENKENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status o
8、f 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 CENELEC member. This European Standard exists in three official versions (English, French, German). A v
9、ersion 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. CENELEC members are the national electrotechnical committees of Austria, Belgium, Denmark, Finland
10、, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fin- Elektrotechnische Nor
11、mung Central Secretariat: rue de Stassart 35, B-1050 Brussels O 1996 Copyright reserved to CENELEC members Ref. No. EN 6158-7 : 1996 E sTDTBSBS-EN bL5O-?-NL1997 m LbZLibb7 0587203 7TO m Page 2 EN 61580-7 : 1996 Foreword The text of document 46B/208/FDIS, future edition 1 of IEC 1580-7, prepared by S
12、C 46B, Waveguides and their accessories, of IEC TC 46, Cables, wires, waveguides, R.F. connectors, and accessories for communication and signalmg, was submitted to the IECCENELEC parallel vote and was approved by CENELEC as EN 61580-7 on 1W07-02. The following dates were fixed - - medium flat rectan
13、gular waveguide (aspect ratio 3:l); - square waveguide; - circular waveguide. 2.2 To determine waveguide performance, project a line horizontally corresponding to a specified mode to cut the a/X axis. Draw a line from this point through the a (mm) line to cut the frequency axis. 2.3 If greater accur
14、acy is required, the cut-off frequencies can be calculated using the relationships listed in clause 4 for the cut-off wavelengths (hc). Cut-off frequency is then given by fc = c/hc, where IC is the velocity of light. 2.4 Examples are given below to illustrate the use of the nomograms. 3 Examples 3.1
15、 Ordinary rectangular waveguides 3.1.1 For ordinary rectangular waveguides the recommended frequency range extends from 25 % above the dominant mode cut-off to 5 % below the cut-off for the next higher order mode. 3.1.2 To determine the normal operating frequency band for, say, R48 waveguide, procee
16、d as follows using the nomogram shown as figure 2: a) project the TE, and TE, lines horizontally to cut the a/h axis at 0,5 and 1,0 respectively; STD-BSI BS EN bL580-7-ENGL 1777 1bZlrbb7 0587203 773 W Page 4 EN 61580-7 : 1996 b) draw a line from the points 0,5 and 1,0 through the point a = 47?55 mm
17、to cut the frequency axis at the points corresponding to the required cut-off frequencies; c) read off the values 3,15 GHz for the TE, mode and 6,31 GHz for the TE, mode. 3.1.3 The normal operating band for R48 is therefore: (3?15 + 25 %) = 3,94 GHz to (6?31 - 5 %) = 5,99 GHz 3.2 Medium flat rectang
18、ular waveguides For these waveguides, suppression of the TE, mode results in a nominal 1,5:0,5 = 3:l bandwidth compared with? 2:l for ordinary rectangular waveguides. The TE, mode is an odd mode which can easily be suppressed by filtering. 3.3 Square waveguides To determine the common cut-off freque
19、ncy for the TE, and TM, modes for a square waveguide with a = 34 mm proceed as follows: a) project the common TE, TM, line horizontally to cut the a/h axis at the point A (see figure 4); b) draw a line from A through a = 34 mm to cut the frequency axis at B, corresponding to the cut-off frequency of
20、 6?24 GHz. 3.4 Circular waveguides To determine the diameter ?a? and the cut-off frequency for a circular waveguide operating up to 11 GHz in the dominant (TE1,) mode only, proceed as follows: a) project the TE, and TM, lines horizontally to cut the a/h axis at the points C and D respectively (see f
21、igure 4); b) allowing for a safety factor of approximately 1 %, draw a line from point D to the point corresponding to 11,l GHz on the frequency axis. This cuts the ?a? line at E corresponding to a value a = 20?7 mm; c) draw a line from C through E to cut the frequency axis at the point F, correspon
22、ding to the cut-off frequency of 8,5 GHz. 4 Formulae for cut-off wavelengths 4.1 Rectangular waveguides For the TE, and TM, modes: 2xG where a = broad dimension of the wave guide; b = narrow dimension of the waveguide. STD- BSIBS EN bL580-7-ENGL 1797 1b24bb9 0587204 bOT- m n 1 2 Page 5 EN 61580-7 :
23、1996 O 1 2 3 415 6 3,832 1,841 3,054 4,201 5,317 6,416 7.501 7,016 5,331 6.706 8.01 5 9,282 10,520 1 1,735 4.2 Circular waveguides m O 1 2 3 4 n 1 2.405 3,832 5,136 6.380 7,588 2 5,520 7,016 8,417 9,761 1 1,065 Icxa Ac =- Xmn 5 8,771 12,339 where a = diameter of the guide; xmn = roots of a Bessel fu
24、nction. The first 14 roots of the appropriate Bessel functions are tabulated below for the TE, (table 1) and TMmn (table 2) modes. NOTE - m and n can be interchanged to give an orthogonal set of modes for square waveguides. Table 1 - Roots of Bessel function for TE, modes Table 2 - Roots of Bessel f
25、unction for TM, modes 6 Page 6 EN 61580-7 : 1996 f 31 2 1 Figure 1 STD-BSI BS-EN bL580-7-NGL 1997 Lb24bb9 058720b 482 Page 7 Figure 2 20 15 10 Figure 3 i (GI STD-BSI BS EN bL58-ENGL 1997 m Lb24bb9 0587208 255 m Page 9 EN 61580-7 : 1996 12 11 10 9 8 7 6 5 4 Figure 4 STDmBSI BS EN bL580-7-ENGL 1797 =
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