In diesem dringend notwendigen Referenzwerk untersuchen die Autoren, renommierte Experten des Fachgebiets, das Prinzip des Elektromagnetismus nach Maxwell und beschreiben die Eigenschaften einer Antenne im Frequenzbereich. Beleuchtet werden ebenfalls die Ausbreitungsverluste in Drahtlosnetzen sowie Ultrabreitband-Antennen und die Mechanismen der Breitbandübertragung von elektrischem Strom und Daten. Der Inhalt im Überblick: - Erörtert die Schwächen von MIMO-System aus theoretischer und praktischer Sicht. - Zeigt, wie sich Basisstationsantennen so einsetzen lassen, dass sie effizienter…mehr
In diesem dringend notwendigen Referenzwerk untersuchen die Autoren, renommierte Experten des Fachgebiets, das Prinzip des Elektromagnetismus nach Maxwell und beschreiben die Eigenschaften einer Antenne im Frequenzbereich. Beleuchtet werden ebenfalls die Ausbreitungsverluste in Drahtlosnetzen sowie Ultrabreitband-Antennen und die Mechanismen der Breitbandübertragung von elektrischem Strom und Daten. Der Inhalt im Überblick: - Erörtert die Schwächen von MIMO-System aus theoretischer und praktischer Sicht. - Zeigt, wie sich Basisstationsantennen so einsetzen lassen, dass sie effizienter arbeiten. - Validiert das Prinzip und die theoretische Analyse der elektromagnetischen Ausbreitung in der drahtlosen Kommunikation. - Zeigt Ergebnisse aus Experimenten, die in der Mathematik und Physik verankert sind.
Tapan K. Sarkar, PhD, is a professor in the Department of Electrical Engineering and Computer Science at Syracuse University, New York, USA. Magdalena Salazar Palma, PhD, is a professor in the Department of Signal Theory and Communications at Universidad Carlos III de Madrid, Spain. Mohammad Najib Abdallah, PhD, is a researcher at Syracuse University.
Inhaltsangabe
Preface xi
Acknowledgments xvii
1 The Mystery of Wave Propagation and Radiation from an Antenna 1
Summary 1
1.1 Historical Overview of Maxwell's Equations 3
1.2 Review of Maxwell-Hertz-Heaviside Equations 5
1.2.1 Faraday's Law 5
1.2.2 Generalized Ampere's Law 8
1.2.3 Gauss's Law of Electrostatics 9
1.2.4 Gauss's Law of Magnetostatics 10
1.2.5 Equation of Continuity 11
1.3 Development of Wave Equations 12
1.4 Methodologies for the Solution of the Wave Equations 16
1.5 General Solution of Maxwell's Equations 19
1.6 Power (Correlation) Versus Reciprocity (Convolution) 24
1.7 Radiation and Reception Properties of a Point Source Antenna in Frequency and in Time Domain 28
1.7.1 Radiation of Fields from Point Sources 28
1.7.1.1 Far Field in Frequency Domain of a Point Radiator 29
1.7.1.2 Far Field in Time Domain of a Point Radiator 30
1.7.2 Reception Properties of a Point Receiver 31
1.8 Radiation and Reception Properties of Finite-Sized Dipole-Like Structures in Frequency and in Time 33
1.8.1 Radiation Fields from Wire-Like Structures in the Frequency Domain 33
1.8.2 Radiation Fields from Wire-Like Structures in the Time Domain 34
1.8.3 Induced Voltage on a Finite-Sized Receive Wire-Like Structure Due to a Transient Incident Field 34
1.8.4 Radiation Fields from Electrically Small Wire-Like Structures in the Time Domain 35
1.9 An Expose on Channel Capacity 44
1.9.1 Shannon Channel Capacity 47
1.9.2 Gabor Channel Capacity 51
1.9.3 Hartley-Nyquist-Tuller Channel Capacity 53
1.10 Conclusion 56
References 57
2 Characterization of Radiating Elements Using Electromagnetic Principles in the Frequency Domain 61
Summary 61
2.1 Field Produced by a Hertzian Dipole 62
2.2 Concept of Near and Far Fields 65
2.3 Field Radiated by a Small Circular Loop 68
2.4 Field Produced by a Finite-Sized Dipole 70
2.5 Radiation Field from a Finite-Sized Dipole Antenna 72
2.6 Maximum Power Transfer and Efficiency 74
2.6.1 Maximum Power Transfer 75
2.6.2 Analysis Using Simple Circuits 77
2.6.3 Computed Results Using Realistic Antennas 81
2.6.4 Use/Misuse of the S-Parameters 84
2.7 Radiation Efficiency of Electrically Small Versus Electrically Large Antenna 85
2.7.1 What is an Electrically Small Antenna (ESA)? 86
2.7.2 Performance of Electrically Small Antenna Versus Large Resonant Antennas 86
2.8 Challenges in Designing a Matched ESA 90
2.9 Near- and Far-Field Properties of Antennas Deployed Over Earth 94
2.10 Use of Spatial Antenna Diversity 100
2.11 Performance of Antennas Operating Over Ground 104
2.12 Fields Inside a Dielectric Room and a Conducting Box 107
2.13 The Mathematics and Physics of an Antenna Array 120
2.14 Does Use of Multiple Antennas Makes Sense? 123
2.14.1 Is MIMO Really Better than SISO? 132
2.15 Signal Enhancement Methodology Through Adaptivity on Transmit Instead of MIMO 138
2.16 Conclusion 148
Appendix 2A Where Does the Far Field of an Antenna Really Starts Under Different Environments? 149
Summary 149
2A.1 Introduction 150
2A.2 Derivation of the Formula 2D²/lambda 153
2A.3 Dipole Antennas Operating in Free Space 157
2A.4 Dipole Antennas Radiating Over an Imperfect Ground 162
