Radio Wave Propagation (eBook)

Preface 5
Contents 7
Chapter 1 Fundamental Concepts: Propagation in Free Space 10
1.1 Free Space Versus Guided Propagation of RadioWaves 10
1.2 The Concept of Power Density 10
1.3 Electric and Magnetic Field Components 12
1.4 Velocity of Propagation and Frequency-Wavelength Relationship 14
1.5 Friis’ Radiation Formula 15
1.6 Band Designation for RadioWaves 16
1.7 RadioWave Propagation Near the Earth 17
1.8 Allocating the Radio Spectrum 19
Chapter 2 The SurfaceWave 22
2.1 Ideal SurfaceWave Field Strength 22
2.2 The Case of a Real Earth 23
2.3 Incorporating Earth Curvature and Atmospheric Refraction 26
2.4 Propagation at Very Low Frequencies 27
Chapter 3 The Sky Wave 32
3.1 The Ionosphere 32
3.2 The Refractive Index of an Ionospheric Layer 35
3.3 Refraction of a Radio Wave in the Ionosphere 36
3.4 The Set of Critical Frequencies 39
3.5 The Virtual Height of an Ionospheric Layer 40
3.6 Maximum Usable Frequency and Skip Distance 44
3.7 Range of the SkyWave 45
Chapter 4 The Space Wave 48
4.1 The Received Field Strength 48
4.2 Effect of Earth Curvature on SpaceWave Propagation 52
4.3 Diffraction 54
4.4 Refraction of the SpaceWave 57
4.5 Effect of Rainfall on SpaceWave Propagation 62
4.6 Atmospheric Attenuation 63
Chapter 5 Noise 66
5.1 What is Noise? 66
5.2 Sources of Noise 67
5.2 Sources of Noise 67
5.3 The Concept of Noise Temperature 68
5.4 The Noise Temperature of a Two Port 68
5.5 Noise Figure 70
5.6 Relationship Between Noise Figure and Output Signal to Noise Ratio 70
5.7 The Noise Properties of a Passive Two Port 71
5.8 Cascaded Two Ports: Friis’ Noise Formula 72
Chapter 6 Examples of Microwave Systems 77
6.1 The Design of Open Microwave Repeater Systems 77
6.2 Propagation Aspects of Satellite Communication Systems 83
6.3 The Propagation Aspects of Cellular Radio 87
6.4 Mobile Wireless Systems 89
Chapter 7 The Effect of Materials on Propagation 94
7.1 Background 94
7.2 Propagation in Homogeneous Media 95
7.3 Frequency Dependence of Material Properties 99
7.4 Interactions with Ideal Interfaces 103
7.5 Reflection from Rough Surfaces 106
7.6 Transmission Through Media 108
7.7 Propagation in Tunnels 109
Appendix A A Simple Introduction to Antennas 113
A.1 Introduction: Radiation Resistance and Radiation Patterns 113
A.2 The Directivity and Gain of an Antenna 116
A.3 The Aperture of an Antenna 118
A.4 Radiated Fields 118
A.5 Some Typical Antennas 121
A.6 Baluns 123
Appendix B The Use of Decibels in Communications Engineering 124
Appendix C The Dielectric Constant of an Ionospheric Layer 126
Index 130