Cable Shielding for Electromagnetic Compatibility

ISBN-13: 9781461565932 / Angielski / Miękka / 2012 / 470 str.

Anatoly Tsaliovich

Opis

The mathematical theory of wave propagation along a conductor with an external coaxial return is very old, going back to the work of Rayleigh, Heaviside, and J. J. Thomson. These words were written by S. A. Schelkunoff back in 1934. Indeed, those early works dealt with signal propagation along the line as well as electromagnetic shielding of the environment inside and/or outside the metallic enclosures. Max- well himself developed pioneering studies of single-layer shielding shells, while a paper with such a "modern" title as "On the Magnetic Shielding of Concentric Spherical Shells" was presented by A. W Rucker as early as 1893 * Such "state of the art" shielding theory created in the last century is even more amazing if you think that at almost the same time (namely, in 1860s), a manuscript of Jules Verne's book, Paris in the. xx Century, was rejected by a publisher because it pre- dicted such "outrageously incredible" electrotechnology as, for example, FAX service by wires and the electrocutioner's chair. (With regard to the last invention, I suspect many readers would rather Jules Verne has been wrong. ) However, although the beginning of electromagnetic shielding theory and its implementation to electronic cables date back more than a century, this dynamic field keeps constantly growing, driven by practical applications.

Spis treści

Preface.- Acknowledgments.- 1. Electronic Cable in an Emi Environment.- 1.1 Introduction to System EMI and EMC.- 1.1.1 System EMI: A Necessary Evil.- 1.1.2 EMC—The Science Of Electronic System Coexistence.- 1.1.3 Electronic System EMI Synthesis and Analysis.- 1.2 Cable EMI Controlling Factors.- 1.2.1 Cable Contribution to System EMI.- 1.2.2 Cable EMI Radiators.- 1.2.3 Cable EMI Generators.- 1.3 Defining and Modeling EMC Performance of Electronic Cable.- 1.3.1 Electronic Cable EMC Performance Parameters.- 1.3.2 Modeling Electronic Cable EMC Performance.- 1.3.3 Electronic Cables as Antennas.- 2. Understanding Cable Shielding.- 2.1 Effects and Problems of Cable Shielding.- 2.1.1 Cable Shielding as an EMI Mitigation Technique.- 2.1.2 A Shield Is a Shield Is a Shield.- 2.1.3 This Confusing World of Cable Shielding.- 2.1.4 What We Have Learned and What’s Missing.- 2.2 Bare Necessities: A Theoretical Detour.- 2.2.1 “He Who Would Search For Pearls, Must Dive Below”.- 2.2.2 Maxwell’s Equations: Refresher.- 2.2.3 Circuit Theory: Refresher.- 2.2.4 Analogy between Wave Propagation in Transmission Lines and Free Space.- 2.3 Shielding—This Is Not Very Simple.- 2.3.1 Applying the Theoretical Tools.- 2.3.2 A System View on Cable Shielding.- 2.3.3 System Definitions of Cable Shielding.- 3. Transfer Parameters of Cable Shields.- 3.1 Figure of Merit of Cable Shield Performance.- 3.1.1 In Search of the Figure of Merit.- 3.1.2 Universal Set of Transfer Parameters.- 3.1.3 Finding EMI Voltage: A Union of Field and Circuit Theories.- 3.2 The Electromagnetic Theory of Solid Homogeneous Shielding Tubes.- 3.2.1 Field Distribution in a Homogeneous Current-Carrying Tube.- 3.2.2 Transfer Parameters of a Solid Homogeneous Tube l.- 3.2.3 Homogeneous Shield Performance Analysis.- 3.3 Practical Tubular Shields.- 3.3.1 Longitudinally Applied Tape l.- 3.3.2 Foil Shields.- 3.3.3 Mesh Shields.- 3.4 Spiral Shields.- 3.4.1 Currents and Fields in Spiral Shields.- 3.4.2 Transfer Parameters of a Spiral Shield.- 3.5 Braided Shield.- 3.5.1 Geometry and Design Parameters of Braided Shield.- 3.5.2 Physical Processes in Braided Shield: Noah’s Ark of Shielding Problems.- 3.5.3 Engineering Model of Braided Shield.- 3.5.4 Braided Shield Performance.- 3.6 Multilayer Shields.- 3.6.1 Multilayer Homogeneous Shields.- 3.6.2 Multilayer Nonhomogeneous Shield Performance.- 3.6.3 The Theory of Multilayer Nonhomogeneous Shields.- 3.6.4 Calculating “Derivative” Shields.- 4. Electromagnetic Coupling and Shielding.- 4.1 Shielding to Decouple and Coupling to Shield.- 4.1.1 Defining Electromagnetic Coupling to Cable Shield.- 4.1.2 A Roadmap to Shielding Coupling Mechanisms.- 4.2 Coupling and Shielding in Static and Stationary Fields.- 4.2.1 Electrostatic Shielding.- 4.2.2 Magnetostatic Shielding.- 4.3 Shielding for Crosstalk Protection.- 4.3.1 Crosstalk Coupling Mechanisms.- 4.3.2 Quasi-stationary Regime in Conductors (and Dielectrics).- 4.3.3 Crosstalk between Shielded Lines in a Wide Frequency Band.- 4.4 Shielding from Radiating Fields.- 4.4.1 The Problems of Radiating Shielding.- 4.4.2 Radiating Fields, Antenna Currents, and Radiation Resistance of Cable Lines and Shields.- 4.4.3 From Transfer Impedance to Shielding Effectiveness.- 4.4.4 EMC and Shielding Performance of Typical Electronic Cables.- 4.5 Grounding and Termination of Cable Shields.- 4.5.1 To Ground or Not To Ground?.- 4.5.2 Challenges of Cable Assembly.- 4.6 Transient Response of Cable Shielding.- 5. Measurement Techniques and Apparatus: The Tools of the Trade.- 5.1 The Proof of the Shielding.- 5.2 System Shielding Effectiveness Measurements.- 5.2.1 System Measurements in Radiating Fields.- 5.2.2 System Measurements in Magnetostatic Fields.- 5.3 Cable Assembly Measurements.- 5.3.1 Cable and Assembly Measurements in Radiating and Magnetostatic Fields.- 5.3.2 Antenna Current Measurements.- 5.3.3 Shielding Effectiveness via Crosstalk Measurements.- 5.4 Transfer Impedance and Capacitive Coupling Impedance Measurements.- 5.4.1 Coaxial Structures: Is There a Sextaxial in the Cards?.- 5.4.2 Terminated Triaxial.- 5.4.3 Line Injection Shielding Effectiveness Measurements.- 5.4.4 Evaluation of Shield Material.- 5.5 Testing in Time Domain.- 5.6 Test Result Correlation And Interpretation.- 5.6.1 “Apples and Oranges”.- 5.6.2 Validating Test Procedures.- 6. Cable Shielding Engineering.- 6.1 System Approach to Shielding Engineering.- 6.1.1 Shielding Engineering Problems.- 6.1.2 To Shield or Not to Shield: the First and the Last Questions.- 6.1.3 “Black Box” Model of Cable Shielding.- 6.2 Cable Shielding Design for EMC Performance.- 6.2.1 Methods and Techniques for Shielding Design.- 6.2.2 Local Problems of Boundary Design.- 6.2.3 Local Optimization.- 6.2.4 Global Braid Optimization by Cost Criterion.- 6.3 Performance Stability and Reliability of Cable Shielding.- 6.3.1 Cable Shield in Physical Environment.- 6.3.2 Effect of Manufacturing Tolerances on the Shield Performance Variability.- 6.3.3 Environmental Stability and Aging of Cable Shielding.- 6.4 Shielding Unlimited.- 6.4.1 “Leaky” Shielding.- 6.4.2 “Plastic” Shielding.- 6.4.3 What’s in the News.