Radiowave propagation : physics and applications

Propagation-the process whereby a signal is conveyed between transmitter and receiver-has a profound influence on communication systems design. Radiowave Propagation provides an overview of the physical mechanisms that govern electromagnetic wave propagation in the Earth's troposphere and ionosphere. Developed in conjunction with a graduate-level wave propagation course at The Ohio State University, this text offers a balance of physical and empirical models to provide basic physical insight as well as practical methods for system design.

Beginning with discussions of propagation media properties, plane waves, and antenna and system concepts, successive chapters consider the most important wave propagation mechanisms for frequencies ranging from LF up to the millimeter wave range, including:

Direct line-of-sight propagation through the atmosphere

Rain attenuation

The basic theory of reflection and refraction at material interfaces and in the Earth's atmosphere

Reflection, refraction, and diffraction analysis in microwave link design for a specified terrain profile

Empirical path loss models for point-to-point ground links

Statistical fading models

Standard techniques for prediction of ground wave propagation

Ionospheric propagation, with emphasis on the skywave mechanism at MF and HF and on ionospheric perturbations for Earth-space links at VHF and higher frequencies

A survey of other propagation mechanisms, including tropospheric scatter, meteor scatter, and propagation effects on GPS systems

Radiowave Propagation incorporates fundamental materials to help senior undergraduate and graduate engineering students review and strengthen electromagnetic physics skills as well as the most current empirical methods recommended by the International Telecommunication Union. This book can also serve as a valuable teaching and reference text for engineers working with wireless communication, radar, or remote sensing systems.

Author Notes

Curt A. Levis was director of The Ohio State University ElectroScience Laboratory from 1961 to 1969. He received the Eta Kappa Nu Distinguished Teaching Award in 1978, 1979, and 1980; he also received a Distinguished Teaching Award from The Ohio University Alumni Association in 1980. Professor Levis is an IEEE Fellow.
Joel T. Johnson is a professor in the Department of Electrical and Computer Engineering and ElectroScience Laboratory at The Ohio State University. His research interests are in the areas of electromagnetics, propagation, and microwave remote sensing. He is an IEEE Fellow and recipient of the ONR Young Investigator, PECASE, and NSF CAREER awards.
Fernando L. Teixeira is an associate professor in the Department of Electrical and Computer Engineering and ElectroScience Laboratory at The Ohio State University, as well as Associate Editor for IEEE Antennas and Wireless Propagation Letters. He is a recipient of the NSF CAREER Award and the triennial USNC-UESI Booker Fellowship.

Preface	p. xi
1 Introduction	p. 1
1.1 Definition of Propagation	p. 1
1.2 Propagation and Systems Design	p. 2
1.3 Historical Perspective	p. 3
1.4 The Influence of Signal Frequency and Environment	p. 4
1.5 Propagation Mechanisms	p. 6
1.6 Summary	p. 12
1.7 Sources of Further Information	p. 14
1.8 Overview of Text	p. 15
2 Characterization of Propagation Media	p. 17
2.1 Introduction	p. 17
2.2 Maxwell's Equations, Boundary Conditions, and Continuity	p. 17
2.3 Constitutive Relations	p. 19
2.4 Dielectric Behavior of Materials: Material Polarization	p. 20
2.5 Material Properties	p. 21
2.51 Simple Media	p. 22
2.6 Magnetic and Conductive Behavior of Materials	p. 30
2.6.1 Equivalence of Ohmic and Polarization Losses	p. 30
References	p. 34
3 Plane Waves	p. 36
3.1 Introduction	p. 36
3.2 D'Alembert's Solution	p. 37
3.3 Pure Traveling Waves	p. 39
3.4 Information Transmission	p. 41
3.5 Sinusoidal Time Dependence in an Ideal Medium	p. 42
3.6 Plane Waves in Lossy and Dispersive Media	p. 46
3.7 Phase and Group Velocity	p. 49
3.8 Wave Polarization	p. 52
References	p. 55
4 Antenna and Noise Concepts	p. 56
4.1 Introduction	p. 56
4.2 Antenna Concepts	p. 56
4.3 Basic Parameters of Antennas	p. 57
4.3.1 Receiving Antennas	p. 62
4.4 Noise Considerations	p. 66
4.4.1 Internal Noise	p. 66
4.4.2 External Noise	p. 68
References	p. 75
5 Direct Transmission	p. 76
5.1 Introduction	p. 76
5.2 Friis Transmission Formula	p. 77
5.2.1 Including Losses in the Friis Formula	p. 78
5.3 Atmospheric Gas Attenuation Effects	p. 80
5.3.1 Total Attenuation on Horizontal or Vertical Atmospheric Paths	p. 82
5.3.2 Total Attenuation on Slant Atmospheric Paths	p. 83
5.3.3 Attenuation at Higher Frequencies and Further Information Sources	p. 84
5.4 Rain Attenuation	p. 85
5.4.1 Describing Rain	p. 87
5.4.2 Computing Rain Specific Attenuation	p. 89
5.4.3 A Simplified Form for Rain Specific Attenuation	p. 90
5.4.4 Computing the Total Path Attenuation Through Rain	p. 92
5.4.5 Attenuation Statistics	p. 96
5.4.6 Frequency Scaling	p. 97
5.4.7 Rain Margin Calculations: An Example	p. 98
5.4.8 Site Diversity Improvements	p. 99
5.5 Scintillations	p. 102
Appendix 5.A Look Angles to Geostationary Satellites	p. 103
References	p. 105
6 Reflection and Refraction	p. 106
6.1 Introduction	p. 106
6.2 Reflection from a Planar Interface: Normal Incidence	p. 106
6.3 Reflection from a Planar Interface: Oblique Incidence	p. 108
6.3.1 Plane of Incidence	p. 109
6.3.2 Perpendicular Polarized Fields in Regions 1 and 2	p. 110
6.3.3 Phase Matching and Snell's Law	p. 111
6.3.4 Perpendicular Reflection Coefficient	p. 113
6.3.5 Parallel Polarized Fields in Regions 1 and 2	p. 113
6.3.6 Parallel Reflection Coefficient	p. 115
6.3.7 Summary of Reflection Problem	p. 115
6.4 Total Reflection and Critical Angle	p. 118
6.5 Refraction in a Stratified Medium	p. 120
6.6 Refraction Over a Spherical Earth	p. 121
6.7 Refraction in the Earth's Atmosphere	p. 127
6.8 Ducting	p. 129
6.9 Ray-Tracing Methods	p. 132
References	p. 134
7 Terrain Reflection and Diffraction	p. 135
7.1 Introduction	p. 135
7.2 Propagation Over a Plane Earth	p. 136
7.2.1 Field Received Along Path R 1 : The Direct Ray	p. 137
7.2.2 Field Received Along Path R 2 : The Reflected Ray	p. 138
7.2.3 Total Field	p. 138
7.2.4 Height-Gain Curves	p. 140
7.3 Fresnel Zones	p. 141
7.3.1 Propagation Over a Plane Earth Revisited in Terms of Fresnel Zones	p. 144
7.4 Earth Curvature and Path Profile Construction	p. 145
7.5 Microwave Link Design	p. 147
7.5.1 Distance to the Radio Horizon	p. 149
7.5.2 Height-Gain Curves in the Obstructed Region	p. 151
7.5.3 Height-Gain Curves in the Reflection Region	p. 154
7.6 Path Loss Analysis Examples	p. 154
7.7 Numerical Methods for Path Loss Analysis	p. 158
7.8 Conclusion	p. 160
References	p. 160
8 Empirical Path Loss and Fading Models	p. 161
8.1 Introduction	p. 161
8.2 Empirical Path Loss Models	p. 162
8.2.1 Review of the Flat Earth Direct plus Reflected Model	p. 163
8.2.2 Empirical Model Forms	p. 164
8.2.3 Okumura-Hata Model	p. 164
8.2.4 COST-231/Hata Model	p. 166
8.2.5 Lee Model	p. 167
8.2.6 Site-General ITU Indoor Model	p. 168
8.2.7 Other Models for Complex Terrain	p. 168
8.2.8 An Example of Empirical Path Loss Model Usage	p. 168
8.3 Signal Fading	p. 170
8.3.1 A Brief Review of Probability Theory	p. 172
8.3.2 Statistical Characterization of Slow Fading	p. 174
8.3.3 Statistical Characterization of Narrowband Fast Fading	p. 176
8.3.4 Example Fading Analyses	p. 183
8.4 Narrowband Fading Mitigation Using Diversity Schemes	p. 184
8.5 Wideband Channels	p. 185
8.5.1 Coherence Bandwidth and Delay Spread	p. 185
8.5.2 Coherence Time and Doppler Spread	p. 186
8.6 Conclusion	p. 187
References	p. 187
9 Groundwave Propagation	p. 189
9.1 Introduction	p. 189
9.2 Planar Earth Groundwave Prediction	p. 190
9.2.1 Elevated Antennas: Planar Earth Theory	p. 194
9.3 Spherical Earth Groundwave Prediction	p. 196
9.4 Methods for Approximate Calculations	p. 199
9.5 A 1 MHz Sample Calculation	p. 200
9.6 A 10 MHz Sample Calculation	p. 203
9.7 ITU Information and Other Resources	p. 204
9.8 Summary	p. 205
Appendix 9.A Spherical Earth Groundwave Computations	p. 211
References	p. 213
10 Characteristics of the Ionosphere	p. 214
10.1 Introduction	p. 214
10.2 The Barometric Law	p. 215
10.3 Chapman's Theory	p. 218
10.3.1 Introduction	p. 218
10.3.2 Mathematical Derivation	p. 219
10.4 Structure of the Ionosphere	p. 226
10.5 Variability of the Ionosphere	p. 229
References	p. 233
11 Ionospheric Propagation	p. 235
11.1 Introduction	p. 235
11.2 Dielectric Properties of an Ionized Medium	p. 237
11.3 Propagation in a Magnetoionic Medium	p. 240
11.3.1 Mathematical Derivation of the Appleton-Hartree Equation	p. 241
11.3.2 Physical Interpretation	p. 247
11.3.3 Ordinary and Extraordinary Waves	p. 247
11.3.4 The Q L and Q T Approximations	p. 248
11.4 Ionospheric Propagation Characteristics	p. 249
11.5 Ionospheric Sounding	p. 250
11.5.1 Ionograms	p. 251
11.5.2 Examples of Actual Ionograms	p. 254
11.6 The Secant Law	p. 257
11.7 Transmission Curves	p. 258
11.8 Breit and Tuve's Theorem	p. 260
11.9 Martyn's Theorem on Equivalent Virtual Heights	p. 261
11.10 MUF, "Skip" Distance, and Ionospheric Signal Dispersion	p. 262
11.11 Earth Curvature Effects and Ray-Tracing Techniques	p. 266
11.12 Ionospheric Propagation Prediction Tools	p. 267
11.13 Ionospheric Absorption	p. 268
11.14 Ionospheric Effects on Earth-Space Links	p. 270
11.14.1 Faraday Rotation	p. 271
11.14.2 Group Delay and Dispersion	p. 273
11.14.3 Ionospheric Scintillations	p. 275
11.14.4 Attenuation	p. 277
11.14.5 Ionospheric Refraction	p. 278
11.14.6 Monitoring TEC Distribution	p. 278
References	p. 280
12 Other Propagation Mechanisms and Applications	p. 282
12.1 Introduction	p. 282
12.2 Tropospheric Scatter	p. 282
12.2.1 Introduction	p. 282
12.2.2 Empirical Model for the Median Path Loss	p. 285
12.2.3 Fading in Troposcatter Links	p. 285
12.3 Meteor Scatter	p. 286
12.4 Tropospheric Delay in Global Satellite Navigation Systems	p. 288
12.5 Propagation Effects on Radar Systems	p. 291
References	p. 293
Index	p. 295

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