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Propagation of Waves

1st Edition - January 1, 1969

Authors: P. David, J. Voge

eBook ISBN:

9 7 8 - 1 - 4 8 3 1 - 5 3 3 7 - 7

Propagation of Waves focuses on the wave propagation around the earth, which is influenced by its curvature, surface irregularities, and by passage through atmospheric layers that… Read more

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Propagation of Waves focuses on the wave propagation around the earth, which is influenced by its curvature, surface irregularities, and by passage through atmospheric layers that may be refracting, absorbing, or ionized. This book begins by outlining the behavior of waves in the various media and at their interfaces, which simplifies the basic phenomena, such as absorption, refraction, reflection, and interference. Applications to the case of the terrestrial sphere are also discussed as a natural generalization. Following the deliberation on the diffraction of the “ground” wave around the earth, this text summarizes the role and properties of the troposphere and ionosphere from a general physical point of view. Examples and maps are provided to illustrate the use of the various methods in the determination of ranges or favorable wavelengths. A brief discussion on problems encountered in the field of space communications is also included. This publication is a good source for students and individuals researching on wave propagation, specifically on the principles of radiation and propagation in a homogeneous, isotropy, and lossless dielectric.

Introduction

Chapter 1. Generalities

1.1 Basic Formula

1.1.1 Transmission Formula

1.1.2 Reception Formula

1.1.3 Formula for the Combined Link

1.2 Statistical Study of Variable Fields

1.2.1 Amplitude Probability Distribution

1.2.2 Speed of Variation

Chapter 2. Currents and Propagation in Various Media

2.1 Properties of Various Types of Currents

2.2 Complex Media. Ionosphere. Terrain

2.3 Equations of Propagation

2.4 Lossless Medium: τ = σ = 0

2.5 Low-Loss Medium

2.6 High-Loss Medium

2.7 Summary

Chapter 3. Passage from One Medium to Another. Reflection. Refraction

3.1 Normal Incidence

3.2 Oblique Incidence

3.2.1 Horizontal Polarization

3.2.2 Vertical Polarization

3.2.3 Discussion of the Oblique Incidence Reflection Coefficients

3.2.4 Resultant Electric Field in the Neighborhood of the Surface of Separation

3.2.5 The Case of a Finite Reflecting Surface. Fresnel Zones

3.2.6 The Case of an Irregular Surface. Rayleigh's Criterion. Diffusion

3.3 Experimental Verifications

Chapter 4. The Role of the Terrain

4.1 General

4.2 The Real Case of Very High Stations

4.3 Stations near the Ground but in Direct Line of Sight. Interference Zone

4.3.1 Distance Small. Earth's Curvature Negligible

4.3.2 Effect of Surface Irregularities

4.3.3 Influence of the Curvature of the Earth

4.3.4 Modification of the Apparent Curvature of the Earth by the Shape of the Ground

4.4 Diffraction (or "Shadow") Zone

4.4.1 General

4.4.2 Stations at Ground Level

4.4.3 Propagation over Inhomogeneous Terrains, Especially Mixed (Land-Sea) Trajectories

4.5 Stations at Any Height

4.5.1 Short Distances. Quasi-Flat Earth

4.5.2 Large Distances. Effect of the Earth's Curvature

4.5.3 "Immediate Proximity" Zone

4.5.4 Second Zone. "Critical" or "Natural" Height

4.5.5 Large Heights. Height Gain Curves

4.5.6 Fishback's Method. Stations at the Critical Height

4.6 Intermediate Zone. Near the Horizon Region

4.7 Conclusions Regarding the Ground Wave

4.8 The Effect of Obstacles

4.8.1 Filiform Obstacles

4.8.2 Spherical Obstacles

4.8.3 Sections of Planes

4.8.4 Cylinders, Paraboloids, Ellipsoids, etc

4.8.5 Miscellaneous Obstacles. Buildings, etc

4.8.6 Usefulness of Certain Obstacles. Passive Reflectors. Radar Targets

Chapter 5. The Role of the Troposphere

5.1 Review of Meteorological Ideas

5.2 Atmospheric Refraction. Equivalent Models for Propagation Calculations

5.3 Influence of the Fine Structure of the Troposphere on Propagation

5.3.1 Fading over Links Which are in Direct Line of Sight

5.3.2 Abnormal Propagation over Long Trajectories not in Direct Line of Sight. Superrefraction

5.3.3 Normal Propagation over Long Trajectories not in Direct Line of Sight

5.4 Absorption by the Atmosphere

Chapter 6. The Role of the Ionosphere

6.1 General

6.2 Methods of Studying the Ionosphere

6.2.1 Vertical Probe at Normal Incidence and Fixed Frequency

6.2.2 Variable Frequency Probes

6.2.3 Probing at Oblique Incidence

6.2.4 Probing by "Back-Scatter"

6.3 Constitution and "Normal" Variations of the Ionosphere

6.3.1 D Region

6.3.2 E Region

6.3.3 F Region

6.3.4 Other Variations. Ionization Maps

6.3.5 Turbulence. Diffusion

6.3.6 Splitting of the Reflected Ray. Role of the Earth's Magnetic Field

6.3.7 Ionization by Meteorites

6.3.8 The Magnetosphere and Interplanetary Space

6.4 Perturbations of the Ionosphere

6.4.1 "Black-outs"

6.4.2 Ionospheric Storms

6.4.3 "Polar Cap" Absorption

6.4.4 Effect of Nuclear Explosions

6.4.5 Echoes with Very Long Delay Times

6.4.6 Wave Interaction ("Luxembourg Effect") by Non-linearity of the Ionosphere

6.4.7 Eclipses

Chapter 7. Interference

7.1 General

7.2 Internal Noise in the Receiver

7.2.1 "Noise Factor" of a Receiver

7.3 Extra-Terrestrial Interference. Noise Radiated by the Atmosphere

7.4 Artificial Interference

7.5 Atmospherics

7.5.1 Form and Duration. Microstructure. Variation with Frequency

7.5.2 Amplitudes. Their Distribution

7.5.3 Localization. Atmospheric Noise Maps

7.6 Other Types of Interference

7.7 Conclusions

Chapter 8. Applications. Propagation in Various Wavelength Ranges

8.1 Propagation of Very Long Waves (Kilometric)

8.1.1 Calculation of Field Strength. Formula of Austin-Cohen, Zinke, Wait, etc

8.1.2 Atmospherics

8.1.3 Obstacles

8.1.4 Examples

8.1.5 Velocity and Phase During Propagation

8.1.6 Propagation along the Lines of Force of the Earth's Magnetic Field

8.2 Propagation of Long and Medium Waves (2000-200 m)

8.2.1 Field Strength and Its Variations. Dispersion

8.2.2 Obstacles, Interference, etc

8.2.3 First Example: Broadcasting

8.2.4 Second Example: Distress Calls at Sea

8.3 Propagation of Intermediate Waves (60-200 m)

8.4 Propagation of Short (Decametric) Waves (10-60 m)

8.4.1 Determination of the Maximum Usable Frequency (MUF)

8.4.2 Determination of the Field Intensity and Lowest Usable Frequency (LUF)

8.4.3 Discussion of the Preceding Results

8.4.4 Examples

8.4.5 First Example: Broadcasting from France to Algeria

8.4.6 Second Example: Paris-Madagascar Aircraft

8.4.7 Third Example: Very Long Range Links

8.4.8 Fading at Decameter Wavelengths

8.5 Propagation of Metric and Shorter Waves

8.5.1 Role of the Ionosphere

8.5.2 Role of the Ground and the Troposphere

8.5.3 Role of Obstacles

8.5.4 The "Radar Equation"

8.5.5 Fading and Interference

8.6 Submarine and Subterranean Propagation

8.7 Space Telecommunications

8.7.1 Influence of the Troposphere

8.7.2 Influence of the Ionosphere

8.7.3 Choice of Frequencies for Space Radiocommunications

8.7.4 Other Propagation Phenomena

8.7.5 Communication with Space Craft during Re-Entry into the Atmosphere

Index