Electromagnetic Shielding

fanghanping · 发表于 2008-12-22 22:44:37

马上注册，结交更多好友，享用更多功能，让你轻松玩转社区。

您需要登录才可以下载或查看，没有账号？注册

x

Preface xi
1 Electromagnetics behind Shielding 1
1.1 Definitions 1
1.2 Notation, Symbology, and Acronyms 3
1.3 Basic Electromagnetics 4
1.3.1 Macroscopic Electromagnetism and Maxwell’s Equations 4
1.3.2 Constitutive Relations 6
1.3.3 Discontinuities and Singularities 9
1.3.4 Initial and Boundary Conditions 11
1.3.5 Poynting’s Theorem and Energy Considerations 11
1.3.6 Fundamental Theorems 13
1.3.7 Wave Equations, Helmholtz Equations, Electromagnetic
Potentials, and Green’s Functions 15
1.4 Basic Shielding Mechanisms 18
1.5 Source Inside or Outside the Shielding Structure
and Reciprocity 18
References 19
2 Shielding Materials 21
2.1 Standard Metallic and Ferromagnetic Materials 21
2.2 Ferrimagnetic Materials 27
2.3 Ferroelectric Materials 28
2.4 Thin Films and Conductive Coatings 30
2.5 Other Materials Suitable for EM Shielding Applications 32
2.5.1 Structural Materials 32
2.5.2 Conductive Polymers 32
v
2.5.3 Conductive Glasses and Transparent Materials 33
2.5.4 Conductive (and Ferromagnetic or Ferrimagnetic) Papers 33
2.6 Special Materials 33
2.6.1 Metamaterials and Chiral Materials 33
2.6.2 Composite Materials 36
2.6.3 Nanomaterials 37
2.6.4 High-Temperature Superconductors 37
References 38
3 Figures of Merit for Shielding Configurations 42
3.1 (Local) Shielding Effectiveness 42
3.2 The Global Point of View 45
3.3 Other Proposals of Figures of Merit 46
3.4 Statistical Methods 50
3.5 Energy-Based, Content-Oriented Definition 52
3.6 Performance of Shielded Cables 53
References 53
4 Shielding Effectiveness of Stratified Media 55
4.1 Electromagnetic Plane Waves: Definitions and Properties 55
4.2 Uniform Plane Waves Incident on a Planar Shield 58
4.2.1 Transmission-Line Approach 58
4.2.2 The Single Planar Shield 61
4.2.3 Multiple (or Laminated) Shields 66
4.3 Plane Waves Normally Incident on Cylindrical Shielding Surfaces 67
4.4 Plane Waves against Spherical Shields 74
4.5 Limits to the Extension of the TL Analogy to Near-Field Sources 75
References 84
5 Numerical Methods for Shielding Analyses 87
5.1 Finite-Element Method 89
5.2 Method of Moments 99
5.3 Finite-Difference Time-Domain Method 110
5.4 Finite Integration Technique 119
5.5 Transmission-Line Matrix Method 124
5.6 Partial Element Equivalent Circuit Method 127
5.7 Case Study: Scattering from a Perfectly Conducting Enclosure
with a Rectangular Aperture 134
References 137
6 Apertures in Planar Metal Screens 144
6.1 Historical Background 145
6.2 Statement of the Problem 146
6.3 Low-Frequency Analysis: Transmission through Small Apertures 147
vi CONTENTS
6.4 The Small Circular-Aperture Case 148
6.5 Small Noncircular Apertures 154
6.6 Finite Number of Small Apertures 155
6.7 Rigorous Analysis for Apertures of Arbitrary Shape: Integral
Equation Formulation 157
6.8 Rules of Thumb 160
References 161
7 Enclosures 164
7.1 Modal Expansion of Electromagnetic Fields inside a Metallic
Enclosure 165
7.2 Oscillations inside an Ideal Source-Free Enclosure 168
7.3 The Enclosure Dyadic Green Function 169
7.4 Excitation of a Metallic Enclosure 172
7.5 Damped Oscillations inside Enclosures with Lossy Walls and
Quality Factor 173
7.6 Apertures in Perfectly Conducting Enclosures 175
7.6.1 Small-Aperture Approximation 176
7.6.2 Rigorous Analysis: Integral-Equation Formulation 178
7.6.3 Aperture-Cavity Resonances 180
7.7 Small Loading Effects 183
7.8 The Rectangular Enclosure 184
7.8.1 Symmetry Considerations 187
7.9 Shielding Effectiveness of a Rectangular Enclosure with a
Circular Hole 188
7.9.1 External Sources: Plane-Wave Excitation 189
7.9.2 Internal Sources: Electric and Magnetic Dipole Excitations 192
References 198
8 Cable Shielding 200
8.1 Transfer Impedance in Tubular Shielded Cables and
Aperture Effects 201
8.2 Relationship between Transfer Impedance and Shielding
Effectiveness 206
8.3 Actual Cables and Harnesses 207
References 208
9 Components and Installation Guidelines 210
9.1 Gaskets 210
9.2 Shielded Windows 214
9.3 Electromagnetic Absorbers 215
9.4 Shielded Connectors 216
9.5 Air-Ventilation Systems 216
CONTENTS vii
9.6 Fuses, Switches, and Other Similar Components 217
References 217
10 Frequency Selective Surfaces 219
10.1 Analysis of Periodic Structures 220
10.1.1 Floquet’s Theorem and Spatial Harmonics 220
10.1.2 Plane-Wave Incidence on a Planar 1D Periodic Structure 222
10.1.3 Plane-Wave Incidence on a Planar 2D Periodic Structure 223
10.2 High- and Low-Pass FSSs 225
10.3 Band-Pass and Band-Stop FSSs 228
10.3.1 Center-Connected Elements or N-Pole Elements 229
10.3.2 Loop-Type Elements 230
10.3.3 Solid-Interior-Type Elements 230
10.3.4 Combinations and Fractal Elements 231
10.4 Degrees of Freedom in Designing FSSs 231
10.5 Reconfigurable and Active FSSs 232
10.6 FSSs and Circuit Analog Absorbers 234
10.7 Modeling and Design of FSSs 235
References 236
11 Shielding Design Guidelines 241
11.1 Establishment of the Shielding Requirements 242
11.2 Assessment of the Number and Types of Functional Discontinuities 243
11.3 Assessment of Dimensional Constraints and Nonelectromagnetic
Characteristics of Materials 244
11.4 Estimation of Shielding Performance 245
References 246
12 Uncommon Ways of Shielding 247
12.1 Active Shielding 247
12.2 Partial Shields 252
12.3 Chiral Shielding 255
12.4 Metamaterial Shielding 256
References 260
Appendix A Electrostatic Shielding 263
A.1 Basics Laws of Electrostatics 264
A.2 Electrostatic Tools: Electrostatic Potential and Green’s Function 266
A.3 Electrostatic Shields 270
A.3.1 Conductive Electrostatic Shields 270
A.3.2 Dielectric Electrostatic Shields 274
A.3.3 Aperture Effects in Conductive Shields 279
References 281
viii CONTENTS
Appendix B Magnetic Shielding 282
B.1 Magnetic Shielding Mechanism 283
B.2 Calculation Methods 286
B.3 Boundary-Value Problems 288
B.3.1 Spherical Magnetic Conducting Shield 288
B.3.2 Cylindrical Magnetic Conducting Shield in a Transverse
Magnetic Field 293
B.3.3 Cylindrical Magnetic Conducting Shield in a Parallel
Magnetic Field 297
B.3.4 Infinite Plane 301
B.4 Ferromagnetic Shields with Hysteresis 314
References 314
Appendix C Standards and Measurement Methods 317
C.1 MIL-STD 285 and IEEE STD-299 319
C.2 NSA 65-6 and NSA 94-106 324
C.3 ASTM E1851 325
C.4 ASTM D4935 326
C.5 MIL-STD 461E 328
C.6 Code of Federal Regulations, Title 47, Part 15 335
C.7 ANSI\SCTE 48-3 337
C.8 MIL-STD 1377 338
C.9 IEC Standards 339
C.10 ITU-T Recommendations 344
C.11 Automotive Standards 346
References 350
Index 353