EN 61580-4-1998 en Methods of Measurement for Waveguides Part 4 Attenuation of Waveguide and Waveguide Assemblies《波导测量方法 第4部分 波导和波导组件的衰减 IEC 61580-4 1997》.pdf

1、BRITISH STANDARD BS EN 61580-4:1998 Incorporating corrigendum July 2006 Methods of measurement for waveguides Part 4: Attenuation of waveguide and waveguide assemblies ICS 33.120.10 BS EN 61580-4:1998 This British Standard was published under the authority of the Standards Board and comes into effec

2、t on 15 July 1998 BSI 2008 ISBN 978 0 580 62330 1 National foreword This British Standard is the UK implementation of EN 61580-4:1998, incorporating corrigendum July 2006. It is identical with IEC 61580-4:1997. The start and finish of text introduced or altered by corrigendum is indicated in the tex

3、t by tags. Text altered by IEC corrigendum July 2006 is indicated in the text by . The UK participation in its preparation was entrusted by Technical Committee EPL/46, Cables, wires and waveguides, r.f. connectors and accessories for communication and signalling, to Subcommittee EPL/46/2, Connectors

4、 and waveguides. A list of organizations represented on this subcommittee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot

5、 confer immunity from legal obligations. Amendments/corrigenda issued since publication Date Comments 30 June 2008 Implementation of IEC corrigendum July 2006EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 61580-4 April 1998 ICS 33.120.10 Descriptors: Waveguides, methods of measurement, attenua

6、tion English version Methods of measurement for waveguides Part 4: Attenuation of waveguide and waveguide assemblies (IEC 61580-4:1997) Mthodes de mesure appliques aux guides dondes Partie 4: Attnuation des guides dondes et des ensembles de guides dondes (CEI 61580-4:1997) Meverfahren fr Hohlleiter

7、Teil 4: Dmpfung von Hohlleitern und Hohlleiterbauteilen (IEC 61580-4:1997) This European Standard was approved by CENELEC on 1998-04-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a nati

8、onal 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 version i

9、n 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, Czech Republic, Denmark,

10、 Finland, 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 fr Elektrotechnisc

11、he Normung Central Secretariat: rue de Stassart 35, B-1050 Brussels 1998 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 61580-4:1998 E2 Foreword The text of document 46B/225/FDIS, future edition1 of IEC61580-4, prepared by SC46B, W

12、aveguides and their accessories, of IEC TC46, 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 EN61580-4 on1998-04-01. The following dates were fixed: Endorsement notice The tex

13、t of the International Standard IEC61580-4:1997 was approved by CENELEC as a European Standard without any modification. Contents Page Foreword 2 1 Scope and object 3 2 General 3 3 Test equipment 3 3.1 Method 1 4 3.2 Method 2 4 3.3 Method 3 5 3.4 Test set-up for method 4 6 4 Procedure 6 4.1 Method 1

14、 6 4.2 Method 2 6 4.3 Method 3 6 4.4 Method 4 7 5 Accuracy 7 5.1 Measurement accuracy with network analysers 7 6 Requirements 7 Figure 1 Test set-up 1 4 Figure 2 Test set-up 2 4 Figure 3 Test set-up 3 5 Figure 4 Analysis for determining the overallmeasurement uncertainty of a test device 8 latest da

15、te by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 1999-01-01 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 1999-01-01 BS EN61580-4:1998 BSI 20083 1 Scope and object This

16、 part of IEC61580 is applicable to attenuation of waveguides and waveguides assemblies. The objective of the test procedures given below is to characterize the attenuation. 2 General The swept frequency method may be used to determine the attenuation. The conditions for attenuation measurements on w

17、aveguides are characterized by access to only one end or a very low loss to be measured or else by both together. Four methods are presented hereinafter in order to cover each case: Method 1: insertion method using swept frequency. It is used for general purposes. Method 2: reflection method using s

18、wept frequency. It is used when only one end is available but there may be some limitations on the insertion loss values that may be measured. Method 3: reflection method using discrete frequencies. It is used when low attenuation is to be measured and where one end only is available. Method 4: uses

19、 an automatic network analyser. The use of an automatic network analyser requires that, for measurement on long lengths of waveguide, particular attention must be given to the number of frequencies and the frequency sweep rate selected. Care must be taken to ensure that any sharp “peaks” or “troughs

20、” in the amplitude response are not effectively smoothed out to produce an erroneous result. 3 Test equipment Suitable test set-ups are shown inFigure 1, Figure 2 andFigure 3. Other equivalent set-ups can be used by agreement between customer and supplier. a) Sweep RF generator: the sweep rate shoul

21、d be slow enough to allow the chart recorder or plotter to reproduce the peak values faithfully. b) Isolator: an isolator or an attenuator is included to prevent reflected waves affecting the output level of the generator. c) Low-pass filter: a low-pass filter or a band-pass filter is included to el

22、iminate spurious harmonic frequencies. In the case where the return loss of the low-pass filter is not good enough, it should be connected before the isolator providing the RF source is not adversely affected. Alternatively, if enough RF power is available, the filter match could be improved by usin

23、g a suitable well-matched attenuator. d) Coupler: the error signal at the coupler(s) detector ports shall be insignificant compared to the signal level being measured. The error signal can be reduced by ensuring that the coupler ports (including adaptors) are well-matched and that the coupler has a

24、high value of directivity (typically better than 45 dB). Coupling values are usually 10 dB to 20 dB with a flat response across the required frequency band. e) Calibrated attenuators: attenuators shall be calibrated in the frequency band of the test. BS EN61580-4:1998 BSI 20084 3.1 Method 1 3.2 Meth

25、od 2 Figure 1 Test set-up 1 Figure 2 Test set-up 2 BS EN 61580-4:1998 BSI 20085 3.3 Method 3 3.3.1 Principle The principle of this method is measuring the Q factor of a one-port cavity. Assuming the waveguide under test is a transmission line with a length l; with the waveguide equivalent admittance

26、 (choose an iris with about 10dB coupling ratio), Y e , in the same plane as the inductance (iris). where is the propagation constant: ( = + j) If Y sis the susceptance of the inductance, the resulting admittance is: When the frequency shifts Y edescribes a circle on polar chart. For f 0at the reson

27、ance: After simplifying and with A = tanh !l Figure 3 Test set-up 3 Y e= coth( l) (1) (2) (3) or Ytot jY s coth () + = Ytot jY s 1 j tan ( tanh ) + tanh j tan + - + = and Re Ytot () tan ( 2 1) tanh + tanh 2 tan 2 + - Y 0 = Y s tan ( ) tanh ( 2 1 ) tanh 2 tan 2 + - = BS EN61580-4:1998 BSI 20086 So, i

28、f we note the overvoltage factor Q 0as: where B is the change of susceptance for f the change of frequency B = lm (Ytot). where 2 gis the wave length in the waveguide and 2 0the wave length in free space. We can compute the attenuation at frequency f 0as: 3.4 Test set-up for method 4 According to th

29、e application, a set-up like Figure 1 or Figure 2 can be used where the network analyser replaces the coupler, generator, isolator, filter and attenuator. The accuracy of system impedance, directivity and source match of Automatic Network Analysers mainly depend on external reference standards conne

30、cted to it during a calibration routine. In addition, if cables between the Automatic Network Analyser and the WUT are used, phase variations in these cables caused by bending may seriously degrade the calibration. 4 Procedure 4.1 Method 1 During calibration, test ports of the equipment are connecte

31、d together. If needed for waveguide measurement, standard adapters shall be included between the two ports. In order to obtain calibration levels corresponding to small reflection coefficients (i.e.large return losses values), a chart shall be established with calibration level curves recorded again

32、st frequency over the specified frequency range. The different levels shall be achieved by either a variable attenuator or by the signal processing unit if it contains a step attenuator. 4.2 Method 2 During calibration the test port of the reflectometer device shall be short-circuited. The reflected

33、 signal corresponds to a reflection of 100% or 0dB attenuation. In order to obtain calibration levels corresponding to small reflection coefficients (i.e.large return losses values), a chart shall be established with calibration level curves recorded against frequency over the specified frequency ra

34、nge. The different levels shall be achieved by either a variable attenuator or by the signal processing unit if it contains a step attenuator. 4.3 Method 3 During calibration the test port of the reflectometer device shall be short-circuited. The signal processing unit shall be adjusted in order to

35、consider the short circuit as the reference plane on the polar chart. (4) (5) (6) (7) Y s 2 1 ( Re Ytot () A) (Re Ytot () A ) A - = After differentiation and simplifying by A 2 1 and Y s df - lm Y e () df - 1 2 - ln 1 A 1 A + - = BS EN 61580-4:1998 BSI 20087 After inserting the inductance (iris) and

36、 connecting the waveguide Q 0shall be determined by the measurement of f 0 , Y 0 , $B, $f. 4.4 Method 4 The typical calibration sequence consists of using an open, short, load and offset load. For waveguide a precision air-filled waveguide and a short is required in place of the open. If the standar

37、ds were perfect, the only errors would be due to the network analyser. Unfortunately, there are numerous errors that potentially can cause difficulties. Many of these are due to mechanical issues involving tight tolerances: dimensional tolerances; stability of phase cable; connector repeatability; g

38、aps at connector interface. Due to difficulties in achieving perfect standards and well-matched waveguides to coax transitions, the TRL calibration method is recommended for waveguide measurements. The TRL calibration method requires three standards. These are Through connection, a high Reflection c

39、onnected to each port and a line connected between the test ports. Furthermore less information is required about the standards using this calibration method than with the traditional calibration approaches. The reference plane is at the mating interface between the waveguide to coax transitions. 5

40、Accuracy Whenever it is possible the reflectometer device shall be in the same standard waveguide dimensions as the WUT. If it is not possible, adapters with small inherent reflections shall be fitted on both ends of the WUT to allow direct connection to the reflectometer device. Computational metho

41、ds may be used to increase the measurement accuracy and to determine the limits of error. 5.1 Measurement accuracy with network analysers Before any measurement with a network analyser, a flow graph model for the errors associated with measuring the S parameters of a two-port device shall be conside

42、red. The errors that affect the S11 measurement are: directivity; source match; reflection tracking. The errors that impact S21 are: source and load match; transmission tracking; isolation. The flow chart below depicts graphically the analysis that shall be followed for determining the overall measu

43、rement uncertainty associated with the measurement of a test device. It should be noted that the instrumentation accuracy has an effect at two stages. Because the calibration standards are measured by the system itself, dynamic accuracy will contribute to uncertainty during the calibration process.

44、Random errors have almost no effect during the calibration process when averaging is employed and good connection techniques adhered to. 6 Requirements Compliance with relevant specification. BS EN61580-4:1998 BSI 20088 Figure 4 Analysis for determining the overall measurement uncertainty of a test

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