EMC of Connectors & Assemblies. Bernhard Mund, bedea Berkenhoff & Drebes GmbH, Herbornerstrasse 100, D Asslar,

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1 Bernhard Mund, Berkenhoff & Drebes GmbH, Herbornerstrasse 100, D Asslar, 1 Bernhard Mund, Berkenhoff & Drebes GmbH, Herbornerstrasse 100, D Asslar, bmund@.com, 2

2 Author: Bernhard Mund Radio & TV Technician, Radio Brand Marburg, Dipl.-Ing. Nachrichten- & Mikroprozessortechnik, FH Giessen, 1984 Berkenhoff&Drebes GmbH, Asslar, Mitarbeiter seit 1985 Manufacturer of Communication cables, (CATV-cables) Responsible: R&D Manager and RF- & EMC-Measurements Standardisation: Chairman of VDE/DKE UK 412.3, Koaxialkabel, Secretary of CENELEC SC 46XA, Coaxial cables Secretary of IEC SC 46A, Coaxial cables Bernhard Mund, Berkenhoff & Drebes GmbH, Herbornerstrasse 100, D Asslar, 3 Overview Physical basics of screening Definitions, electrical length, Coupling transfer function Test procedures Absorbing clamp procedure, wire injection Triaxial procedure Transfer impedance short/short & short matched Screening attenuation Calculation of Z T into a S Special connector problems Discussion Bernhard Mund, Berkenhoff & Drebes GmbH, Herbornerstrasse 100, D Asslar, bmund@.com, 4

3 Definitions, electrical length low frequencies: Transfer impedance high frequencies: Screening attenuation I 2 U 1 l < λ/10 I 2 U Z T = I 2 1 a S = 10 log( P1 / P2 ) = 20 log( U1 / U 2) l << λ/4 [mω/m] Ratio of two powers --> length independent U 1 C T I 2 Y T = I 2 U1 l Wave length λ = ( c 0 vk )/ f Ratio of U/I = R --> lengt dependent Z = Z + Z TE F T [pf/m] electrical long: f c electrical short: c o > o f < 2 l εr1 εr2 10 l εr1 (EN ) Bernhard Mund, Berkenhoff & Drebes GmbH, Herbornerstrasse 100, D Asslar, bmund@.com, 5 Calculated Coupling transfer function T nf a s and Z T vs. frequency T s, n f = ( Z ± Z ) F T Z Z l S 2 n f db T f Tn n = near End f = far End L = 1 m ε r1 =2,3 ε r2 = 1,0 Z F =0 10 khz 100 khz 1 MHz 10 MHz fcn fcf 1 GHz 10 GH Transfer impedance Screening attenuation Frequenz Bernhard Mund, Berkenhoff & Drebes GmbH, Herbornerstrasse 100, D Asslar, bmund@.com, 6

4 Absorbing clamp procedure Screening attenuation from 30 MHz to 1000 MHz MDS MHz to 2500 MHz MDS 22 absorber test length absorber generator receiver current transformer screen under test matching resistor IEC resp. EN Bernhard Mund, Berkenhoff & Drebes GmbH, Herbornerstrasse 100, D Asslar, 7 Procedure with injection wire Transfer impedance up to 1 GHz, matching of injection wire 20 db min! OUT R A B 1 1 Network analyser 2 matching pad 20 db 3 power splitter 4 matching device 5 cable under test 6 connector under test 7 matching resistor 8 injection wire IEC resp. EN Bernhard Mund, Berkenhoff & Drebes GmbH, Herbornerstrasse 100, D Asslar, bmund@.com, 8

5 Triaxial-procedure, principle test set-up Transfer impedance and Screening attenuation DC up to and above 12 GHz with only one test set-up generator screen under test tube matching resistor receiver screening cap IEC Transfer impedance, IEC Screening attenuation, EN , Bernhard Mund, Berkenhoff & Drebes GmbH, Herbornerstrasse 100, D Asslar, 9 measured Coupling transfer function RG 058 Transfer impedance Screening attenuation as/[db] , Frequency f/[mhz] Bernhard Mund, Berkenhoff & Drebes GmbH, Herbornerstrasse 100, D Asslar, bmund@.com, 10

6 Comparison of the test procedures Absorbing clamp procedure Screening attenuation 30 MHz to 1 GHz Injection wire Procedure Transfer impedance up to 1 GHz Triaxial Procedure Transfer impedance and Screening attenuation DC up to 12 GHz with only one test set-up! Bernhard Mund, Berkenhoff & Drebes GmbH, Herbornerstrasse 100, D Asslar, bmund@.com, 11 Comparison of the test procedures Absorbing clamp procedure Injection wire Procedure Foto: Günther Quednau Screening attenuation 30 MHz up to 1 (2,5) GHz Transfer impedance up to 1 GHz Triaxial Procedure Transfer impedance & Screening attenuation DC up to 12 GHz with only one test set-up! Bernhard Mund, Berkenhoff & Drebes GmbH, Herbornerstrasse 100, D Asslar, bmund@.com, 12

7 Triaxial test set-up for Connectors with Tube in tube connector under test mating connector generator receiver RF-tight tube screening cap connecting cable RF-tight tube in tube Tube in tube -procedure IEC , Transfer impedance, Screening & Coupling attenuation of connectors and assemblies Bernhard Mund, Berkenhoff & Drebes GmbH, Herbornerstrasse 100, D Asslar, 13 Test of cable assemblies tube mating connector assenbly under test generator receiver connecting cable screening cap RF-tight tube in tube IEC , Tube in tube - procedure (Connecctors & Assemblies) Bernhard Mund, Berkenhoff & Drebes GmbH, Herbornerstrasse 100, D Asslar, bmund@.com, 14

8 larger connectors and connecting hardware generator tube Connector under test receiver tube in tube connecting cable test head with screening cap housing IEC Bernhard Mund, Berkenhoff & Drebes GmbH, Herbornerstrasse 100, D Asslar, 15 Triaxial procedure with housing and Tube in tube Bernhard Mund, Berkenhoff & Drebes GmbH, Herbornerstrasse 100, D Asslar, 16

9 Triaxial procedure, tube in tube with short circuit IEC screening cap contact slice short circuit screen tube in tube mating connectors under test Transfer impedance up to 100 MHz Bernhard Mund, Berkenhoff & Drebes GmbH, Herbornerstrasse 100, D Asslar, 17 Triaxial procedure, tube in tube, matched IEC screning cap contact slice matching resistor screen tube in tube mating connector under test Transfer impedance up to 100 MHz Screening attenuation up to 12 GHz with one test set-up Bernhard Mund, Berkenhoff & Drebes GmbH, Herbornerstrasse 100, D Asslar, 18

10 Measuring of Coupling attenuation Coupling attenuation is the sum of Unbalance attenuation of the balanced pair and the Screening attenuation of the screen cable under tube symmetrisc/ asymmetric generator load balun screening cap receiver Bernhard Mund, Berkenhoff & Drebes GmbH, Herbornerstrasse 100, D Asslar, 19 Triaxial procedure, tube in tube with symm/asymm IEC Schirmhülse Kontaktscheibe symmetrisch/ asymmetrischer Lastwiderstand Schirm Verlängerungsrohr paariger, zu prüfender Stecker Transfer impedance up to 100 MHz Screening attenuation up to 12 GHz Coupling attenuation up to 1,2 GHz Bernhard Mund, Berkenhoff & Drebes GmbH, Herbornerstrasse 100, D Asslar, 20

11 Calculation of Transfer impedance into Screening attenuation general: 20 db/decade a s = 20 log 10 Z Z Z 1 T l 2 T f Tn 20 db/decade: a a S S = 20 log = 20 log ZT l l Z1Z2ω ± v2 v1 ZTc0 Z Z ω ε ± 1 2 r2 The outer circuit (Z 2 ) influences the screening attenuation ε r1 10 khz 100 khz 1 MHz 10 MHz fcn fcf 1 GHz 10 GH Transfer impedance Screening attenuation l length of cable under test; Z 1 characteristic impedance of the cable; Z 2 characteristic impedance of the outer circuit; ε r1 Dielectric constant of the cable; ε r2 Dielectric constant of the outer circuit; v 1 velocity ratio of the cable; v 2 velocity ratio of the outer circuit; c 0 velocity of light in vacuum; ϖ circular frequency = 2πf Bernhard Mund, Berkenhoff & Drebes GmbH, Herbornerstrasse 100, D Asslar, bmund@.com, 21 Common problems on connector test test rig connector under test matching connector connecting cable Kopplungswiderstände addieren sich! Bernhard Mund, Berkenhoff & Drebes GmbH, Herbornerstrasse 100, D Asslar, bmund@.com, 22

12 Conclusion 1 The screening effectiveness of Cables & Connectors is given as Transfer impedance Z T in the lower frequency range and as Screening attenuation a S in the upper frequency range At screened balanced Cables and Connectors the Coupling attenuation a C is the measure of the screening effectiveness as sum of the Unbalance attenuation of the pair and the screening attenuation of the screen. Test procedures for Cables & Connectors are Absorbing clamp procedure, Injection wire procedure and the Triaxial procedure With the Triaxial procedure (CoMeT) the Transfer impedance Z T and the Screening attenuation a S of Cables & Connectors can be measured in the frequency range from DC up to 12 GHz with one test set-up. Furthermore, the Coupling attenuation a C as sum of the Unbalance attenuation of the pair and the screening attenuation of the screen can be measured with the Triaxial procedure Bernhard Mund, Berkenhoff & Drebes GmbH, Herbornerstrasse 100, D Asslar, bmund@.com, 23 Conclusion 2 With the Triaxial test procedure the Transfer impedance Z T can be measured with short circuit or matched. The Triaxial test procedure is standardised in IEC /-4-4 and in EN for cables, and in IEC for connectors Whereas EMC-test procedures are established well for Communication cables, there are different open questions on testing of Cables & Connectors, especially concerning connecting cables/connection techniques of the connectors under test, matching of connectors and influence of mated connectors. Further information: Messtechnik contact persons: Thomas.schmid@rosenberger.de, rdamm@.com, bmund@.com Bernhard Mund, Berkenhoff & Drebes GmbH, Herbornerstrasse 100, D Asslar, bmund@.com, 24

13 International standards for Triaxial procedure IEC TR Introduction to EMC measurements IEC Surface transfer impedance - Triaxial method IEC IEC Shielded screening attenuation, test method for measuring of the screening attenuation "a s " up to and above 3 GHz Shielded screening attenuation, test method for measuring the Transfer impedance Z T and the screening attenuation a S of RF-Connectors up to and above 3 GHz; Tube in Tube method IEC IEC/PAS Ed1 IEC EN Coupling attenuation, triaxial method Shielded screening attenuation test method for measuring the Screening Effectiveness of Feedtroughs and Electromagnetic Gaskets Communication cables - Specifications for test methods Part 1-6: Electrical test methods -Electromagnetic performance (includes IEC and IEC ) Bernhard Mund, Berkenhoff & Drebes GmbH, Herbornerstrasse 100, D Asslar, bmund@.com, 25 Literatur [1] Bernhard Mund, Thomas Schmid: Messen der Schirmdämpfung von Steckverbindern, Kabeldurchführungen und EMV-Dichtungen, 3. Anwenderkongress Steckverbinder 2009, Vogel Verlag, Würzburg [2] Bernhard Mund: EMC of Cables & Connectors & Test methods, EMC Zurich 2007 [3] Bernhard Mund: Measuring the EMC on RF-connectors and connecting hardware, Tube in tube test procedure, IWCS (International wire & cable symposium) 2004, Philadelphia [4] Thomas Hähner und Bernhard Mund: Measurement of the screening effectiveness of connectors & cable assemblies: International Wroclaw Symposium on Electromagnetic Compatibility, EMC 2002 [5] Thomas Hähner und Bernhard Mund: Background, content and future of the EMC measurement standard pren , Open / shielded test methods, International Wroclaw Symposium on Electromagnetic Compatibility, EMC 2000 [6] Otto Breitenbach, Thomas Hähner und Bernhard Mund: Kabelschirmung im Frequenzbereich von MHz bis GHz, erweiterte Anwendung eines einfachen Meßverfahrens, Frequenz 1-2/1999 S [7] Lauri Halme, Rauno Kytönen, "Background and introduction to EM screening (shielding) behaviours and measurements of coaxial and symmetrical cables, cable assemblies and connectors", IEE Colloquium on screening effectiveness measurements, Savoy Place London, 6 May 1998 Bernhard Mund, Berkenhoff & Drebes GmbH, Herbornerstrasse 100, D Asslar, bmund@.com, 26

14 Thanks for your attention Bernhard Mund, Berkenhoff & Drebes GmbH, Herbornerstrasse 100, D Asslar, 27 Berkenhoff & Drebes GmbH, D Asslar, Germany ca. 325 MA ca. 35 Mio EUR seit 1995 selbständig durch Management-Buy-out 1. Ziel ist die Erhaltung der Arbeitsplätze! - Hersteller von Kommunikationskabeln - Monofile (Techn. Fäden) - Feinseile - Zieh-und Presswerkzeuge - Messtechnik - Lichttechnik Bernhard Mund, Berkenhoff & Drebes GmbH, Herbornerstrasse 100, D Asslar, bmund@.com, 28