1、BRITISH STANDARDBS EN 2591-221:2007Aerospace series Elements of electrical and optical connection Test methods Part 221: Voltage Standing Wave Ratio (VSWR)ICS 49.060g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g
2、48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN 2591-221:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 June 2008 BSI 2008ISBN 978 0 580 56475 8National forewordThis British Standard is the UK implementation of
3、EN 2591-221:2007. The UK participation in its preparation was entrusted to Technical Committee ACE/6, Aerospace avionic electrical and fibre optic technology.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include
4、 all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.Amendments/corrigenda issued since publicationDate CommentsEUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 2591-221Decembe
5、r 2007ICS 49.060English VersionAerospace series - Elements of electrical and optical connection- Test methods - Part 221: Voltage Standing Wave Ratio(VSWR)Srie arospatiale - Organes de connexion lectrique etoptique - Mthodes dessais - Partie 221 : Ratio dOndesStationnairesLuft- und Raumfahrt - Elekt
6、rische und optischeVerbindungselemente - Prfverfahren - Teil 221:StehwellenverhltnisThis European Standard was approved by CEN on 27 April 2006.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a na
7、tional standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in
8、any other language made by translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Est
9、onia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISC
10、HES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2007 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 2591-221:2007: E2 Contents Page Foreword3 1 Scope 4 2 Normative references 4 3 Preparation of specimens
11、.4 4 Apparatus .5 5 Procedure .6 6 Requirement.6 7 Detail to be specified.6 Annex A (normative) Definition of S parameters .8 BS EN 2591-221:20073 Foreword This document (EN 2591-221:2007) has been prepared by the Aerospace and Defence Industries Association of Europe - Standardization (ASD-STAN). A
12、fter enquiries and votes carried out in accordance with the rules of this Association, this Standard has received the approval of the National Associations and the Official Services of the member countries of ASD, prior to its presentation to CEN. This European Standard shall be given the status of
13、a national standard, either by publication of an identical text or by endorsement, at the latest by June 2008, and conflicting national standards shall be withdrawn at the latest by June 2008. Attention is drawn to the possibility that some of the elements of this document may be the subject of pate
14、nt rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyp
15、rus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 2591-221:20074 1 Scope This st
16、andard specifies a measurement method of VSWR, in the required frequency bandwidth of coax contacts or connectors with characteristic impedance. It shall be used together with EN 2591-100. The measurement is carried out according to vectorial method using “S” parameters (see definition in Annex A).
17、2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 2591-100, Aerospace ser
18、ies Elements of electrical and optical connection Test methods Part 100: General. 3 Preparation of specimens Method “A” This method is applicable, when a calibrated adapter, for the series of connectors or contacts to be tested, exists. The sampling shall include, for each specified cable, one secti
19、on of coaxial cable with device under test at both ends. The section is constituted/described only as follows (see Figure 1): (600 2,5) mm of coaxial cable 1 male coaxial device 1 female coaxial device Key 1 Male coaxial device 2 Female coaxial device 3 Coaxial cable; Lg. = (600 2,5) mm Figure 1 BS
20、EN 2591-221:20075 Method “B” This method is applicable, when a calibrated adapter, for the series of connectors or contacts to be tested, exists. The sampling shall include for each specified cable, one section of coaxial cable with standard connectors at both end, and the device under test in the m
21、iddle of the section of the cable. The section is constituted/described only as follows (see Figure 2): (600 5) mm of coaxial cable divided in 2 (2 300 mm) 1 male coaxial standard connector (SMA, Nor TNC type ) 1 female coaxial standard connector (SMA, Nor TNC type ) 1 male coaxial device 1 female c
22、oaxial device Key 1 Coaxial (Std) male connector 2 Device under test 3 Coaxial (Std) female connector 4 Coaxial cable; Lg. = 2 (300 2,5) mm Figure 2 4 Apparatus The apparatus shall comprise measuring equipment which includes (see Figure 3): vector network analyser calibration kit standard precision
23、adapters a 75 kit of transformation, to perform measurement from 50 network analyser, when it is necessary. BS EN 2591-221:20076 5 Procedure 5.1 Calibration Select frequency range to be measured and number of sampling points. Carry out the complete calibration of network analyser, Part 1 and Part 2
24、(“S” Parameters, S11, S12, S21and S22) using the calibration kit according to instructions specified by network analyser manufacturer. 5.2 Measurement Method A Connect the section in measure on network analyser, using if necessary, standards accurate adapters, and perform the measurement. The VSWR o
25、f one coaxial device is determined by using the temporal response (time domain) and a function called “GATE“ to isolate the coaxial device, which must be connected to the standard precision adapter. Method B Connect the section in measure on network analyser, using if necessary, standards accurate a
26、dapters, and perform measurement. The VSWR of the two mated coaxial devices is determined by using the temporal response (time domain) and a function called “GATE“ to isolate the two mated coaxial devices, from the coaxial cable. 6 Requirement The Voltage Standing Wave Ratio (VSWR) does not exceed s
27、pecified values in the product standard. 7 Detail to be specified The following items shall be specified: coaxial devices (contact or connector) part numbers coaxial cables part number standard coaxial connectors part number network analyser, manufacturer, type and serial number frequency range samp
28、ling point number standard precision adapter part number measurement impedance (50 or 75 ) for coaxial contact, connection length wiring instruction and tooling for thread coupling connectors, the coupling torque of the coupling ring. BS EN 2591-221:20077 Key 1 Vector network analyser 2 RF generator
29、 and “S” parameter test set Legend Precision hermaphroditic connectors Standard Precision Adapters Figure 3 Hermaphrodite Interface Standard Coaxial Connector Interface Device Under Test Interface BS EN 2591-221:20078 Annex A (normative) Definition of S parameters A.1 Effective Power of a Sinusoidal
30、 source Consider an E.M.F. source, E, measured in Vrmswith an internal impedance Zgand a load impedance Z. The applied power P dissipated in Z is defined as () ()Z eZZE*Z*Z*EZZZEe*I V e Pggg+=+=22)()(P is a maximum when *ZZg= (balanced load). This maximum power is known as the effective or RMS nota
31、Root Mean Squared power for a given source (E, Zg) and can be expressed as Prms= )(2gdZeEP=4In general, when Z has a different value to Zg, we define P as +=221)(gggZZ*Z-ZZeEP4where ggZZ*ZZ+is known as the Power Reflection Coefficient. The power dissipated in Z can be expressed as the difference of
32、two powers, and when the source (E, Zg) power is maximum and when Z Zg, the amount of power reflected towards the source is equal to 2ggZZ*Z-Z+BS EN 2591-221:20079 A.2 Waves Incident and Reflected (Kurokawa Waves) Let us define an impedance, Z, in terms of a potential difference, V, and a current I.
33、 We also define an Incident Wave, a, and a Reflected Wave, b, with respect to a Reference Resistance, Rg, as follows: the power dissipated in Z = P = |a|2 |b|2 the effective power generated by the source (E, Rg) = Prms= |a|2Expressing a and b in terms of V, I, Rg, gives: ggRI R Va2+= ggRI R Vb2= If
34、Z is supplied by the source (E, Rg) we can state that E = V + Rg.I which automatically validates Prms = |a|2. NOTE - Rgis known as the Reference Resistance for the “waves“ a and b - The word wave is written inside speech marks because a and b do not show the typical electromagnetic behaviour associa
35、ted with classical waves they are rather Power Waves - The definition of a and b is independent of that fact that the dipole Z is fed by a source of an internal resistance Rg- The power dissipated in Z is independent of the characteristics of the source and is always equal to |a|2|b|2- The ratio of
36、the waves b to a is equal to (when V = Z.I) ggR ZR - Zab+= which is the Reflection Coefficient of the impedance Z with respect to the reference resistance Rg. BS EN 2591-221:200710 A.3 S Parameters of a quad pole Let us apply the precedent definition to the input and output of a quad pole device. Th
37、is time we define an incident and reflected wave, a1and b1, for the input side and incident and reflected wave, a2and b2, for the output side, relative to the input and output reference resistances, R1and R2. 111112 R I RVa+= 222222 R I RVa+= 111112 R I RVb= 222222 R I RVb= We can state that the sys
38、tem is linear and we can therefore re-write the above equations to express on variable in function of two of the other unknowns. b1= S11 a1+ S12 a2b2= S21 a1+ S22 a2These S Parameters are also known as the system distribution parameters and characterise the quad pole in function of its input and out
39、put reference resistances, R1and R2. NOTE These S Parameters define the quad pole at a given frequency A.4 Physical Signification and Interest of S Parameters A.4.1 Physical significance of S11If S11= b1/a1, where a2= 0, then a2is equivalent to V2= R2.I2, the output of the quad pole is therefore clo
40、sed loop on R2and if Zeis the input impedance of Q, then in these conditions, we can state that V1 = Ze.I1and S11is the input reflection coefficient with respect to R1when the output impedance = R2. 1111RZRZSee+=BS EN 2591-221:200711 A.4.2 Physical significance of S22In the same way, if S22= b2/a2th
41、en when a1= 0, the input is closed loop on R1and under these conditions if Zois the output impedance, we obtain S22is the input reflection coefficient with respect to R2when the input impedance = R1. The Smmparameters are therefore defined as the Reflection Coefficients. A.4.3 Physical significance
42、of S21If S21= b2/a1then when a2= 0, the output is closed loop on R2and therefore 111222211221IRVIRVRRabS+= If we assume that the quad pole Q is supplied by a source (E, R1) then E = V1+ R1.I1and V2= R2.I2The quad pole being supplied by a source of impedance R1and with a load R2will have a S Paramete
43、r S21proportional to a voltage gain called the System Transmission Coefficient. If we take the square of S21then we obtain )/12122221222221RMS PowerinRMS Power 44R (E, R RERVRREVS = where |S21|2is the Composite Power Gain. 2222RZRZSss+= EVRRS221212= BS EN 2591-221:200712 A.4.4 Physical significance
44、of S12We can do a similar calculation as above and we will find that, for a quad pole Q supplied by a source (E, R2) and whose input is closed loop on R1, the S12parameter is defined by EVRRS112212= S21is called the Inverse Transmission Coefficient. These S Parameters are used to characterise the ju
45、nctions in high frequency applications because they possess a number of advantages: these parameters are measurable at R1and R2. In practice we choose standard values for resistances R1and R2such as 50 ohms or 75 ohms. It is much easier to measure variables over a known resistance than on an open ci
46、rcuit (Z Parameters) or in a short circuit (Y Parameters); in closing each side of the circuit allows frequency sweeping; as the termination resistances R1and R2are dissipative, the risks of instability during the analysis of the active quad pole are decreased (which is not the case for open or shor
47、t-circuits): a simple device already exists to separate a and b waves at high frequencies. This device is the directional coupler. BS EN 2591-221:2007blankBS EN 2591-221:2007BSI Group Headquarters389 Chiswick High Road,London W4 4AL, UKTel +44 (0)20 8996 9001Fax +44 (0)20 8996 Standards Institute (
48、BSI)BSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter.RevisionsBritish Standards are updated by amendment or revision. Users of British Standards should
49、make sure that they possess the latest amendments or editions.It is the constant aim of BSI to improve the quality of our products and services. We would be grateful if anyone finding an inaccuracy or ambiguity while using this British Standard would inform the Secretary of the technical committee responsible, the identity of which can be found on the inside front cover. Tel: +44 (0)20 8996 9000 Fax: +44
