کاربردهای عملی تکنیک‌های حدی در الکترومغناطیس

Antenna, wireless communication and other electrical engineers use asymptotic techniques for solving electromagnetic problems when the electrical size of a given scenario is large in comparison to the wavelength. This practical book offers in-depth coverage of this area, showing how to apply these techniques to the analysis of complex electromagnetic problems in order to obtain results with an exceptionally high degree of accuracy. Focusing on two highly-effective methods - the uniform theory of diffraction (UTD) and physical optics (PO), this book is unique in that it emphasizes how to solve real-world problems, rather than simply explaining theory like other books on the market. This first-of-its-kind resource show professionals how to apply this knowledge to a wide range of projects in the field, including antenna design, mobile communications, and RCS (revision control system) computation. This authoritative book is supported with more than 100 illustrations and over 250 equations. Practical Applications of Asymptotic Techniques in Electromagnetics......Page 2 Contents......Page 6 Preface......Page 10 1.1 ASYMPTOTIC TECHNIQUES AND REAL-WORLD PROBLEMS......Page 14 1.2 STRUCTURE OF THIS BOOK......Page 17 References......Page 18 2.1 OVERVIEW OF THE GEOMETRIC MODELING OF COMPLEX OBJECTS......Page 20 2.2 RATIONAL BEZIER CURVES......Page 23 2.3 RATIONAL B-SPLINE CURVES......Page 26 2.4 RATIONAL BEZIER SURFACES......Page 29 2.5 RATIONAL B-SPLINE SURFACES......Page 35 2.6 TRANSFORMATION FROM NURBS REPRESENTATION TO BEZIER REPRESENTATION......Page 36 2.7.1 Computation of Unit Normal Vectors......Page 38 2.7.2 Computation of Principal Curvature Radii and Principal Directions......Page 39 References......Page 41 3.1 HISTORICAL OVERVIEW......Page 44 3.2 GEOMETRICAL OPTICS EQUATIONS......Page 48 3.2.2 Polarization......Page 49 3.2.3 Phase......Page 50 3.2.4 Amplitude......Page 51 3.3.1 Electromagnetic Field Calculation......Page 53 3.3.2 Determination of the Direct Rays......Page 54 3.4.1 Electromagnetic Field Calculation......Page 56 3.4.2 Determining Reflected Rays and Computing Reflection Points......Page 61 3.5.1 Electromagnetic Field Calculation......Page 63 3.5.2 Determining Diffracted Rays and Computing Diffraction Points......Page 68 3.6.2 Determining Double Effect Rays......Page 70 3.7.1 Electromagnetic Field Calculation......Page 75 3.7.2 Determining Creeping Wave Trajectories......Page 78 References......Page 82 4.1 INTRODUCTION TO PO/PTD......Page 86 4.2 PHYSICAL OPTICS FOUNDATIONS......Page 88 4.3.1 Numerical Integration......Page 94 4.3.2 Ludwig Method......Page 95 4.3.3 Method of Plane Facets......Page 96 4.3.4 Method of Numerical Quadrature......Page 99 4.3.5 Method of the Graphical Processing of the Image......Page 102 4.3.6 Current Modes......Page 103 4.4 THE STATIONARY PHASE METHOD......Page 106 4.5.1 Multiple Reflections Between Plane Surfaces......Page 118 4.5.2 Double Reflection Between a Plane Surface and a Curved Surface......Page 120 4.5.3 Double Reflection Between Curved Surfaces Using the SPM......Page 121 4.6 PHYSICAL THEORY OF DIFFRACTION AND THE EQUIVALENT CURRENT METHOD......Page 123 4.7 INTRODUCTION OF RADAR ABSORBING MATERIALS (RAM) IN THE PO FORMULATION......Page 127 References......Page 128 5.1 ACCELERATION TECHNIQUES APPLIED TO HIGH-FREQUENCY PROBLEMS......Page 132 5.2.1 Normal Vector Criterion......Page 135 5.2.2 Intersection with the Bounding Box......Page 136 5.3.1 The Angular Z-Buffer (AZB) Algorithm......Page 137 5.3.2 Space Volumetric Partitioning (SVP)......Page 140 5.4.1 Application to the Shadowing of the Direct Ray......Page 141 5.4.2 Application to the Shadowing of an Intermediate Ray......Page 145 5.4.3 Application to the Determination of the Reflection Points......Page 148 5.4.4 Application to Multiple-Order Reflections......Page 153 5.4.5 Application to the Shadowing of the Diffracted Ray......Page 154 5.5 COMBINATION OF AZB-SVP FOR THE ANALYSIS IN THE NEAR ZONE......Page 155 5.6.1 Application to Plane Facets......Page 157 5.6.2 Application to Curved Surfaces......Page 158 5.6.3 Application to Double- and Higher-Order Effects Between Plane Facets......Page 159 References......Page 160 6.1 OVERVIEW OF ASYMPTOTIC TECHNIQUE CODES......Page 162 6.2 RESULTS OBTAINED WITH FASANT......Page 163 6.2.1 Radiation Pattern of Antennas On-Board the Jason and Stentor Satellites......Page 164 6.2.2 Radiation Pattern of Antennas On-Board the International Space Station (ISS)......Page 178 6.2.3 Satellite Indoor Reception in Vienna......Page 190 6.2.4 Wind Turbines......Page 198 6.3 RESULTS OBTAINED WITH POGCROS AND NUMERICAL EVALUATION OF THE PO INTEGRAL......Page 203 6.3.1 RCS of a Scud Missile......Page 204 6.3.2 Analysis of the Range-Profile Image of the Tabarca Ship......Page 209 6.3.3 Cavity Analysis......Page 213 6.3.4 Analysis of a Reflector Antenna......Page 215 References......Page 220 About the Authors......Page 222 Index......Page 226 Introduction Geometric description of the bodies and computation of geometric parameters Geometrical optics and uniform theory of diffraction (GO/UTD) Physical optics and physical theory of diffractions (PO/PTD) Acceleration techniques Applications. 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