Electromagnetic Waves in Stratified Media

Abstract

This book [1] was written at an important point in the development of applications of electromagnetic (radio) waves to communications, navigation, and remote sensing. Such applications require accurate propagation predictions for a variety of path conditions, and this book provides the theoretical basis for such predictions. The book is based on fundamental research in electromagnetic wave propagation that James R. Wait performed in the Central Radio Propagation Laboratory (CRPL) of NBS from 1956 to 1962. The mathematical theory in the book is very general, and the "stratified media" models are applicable to the earth crust, the troposphere, and the ionosphere. The frequencies of the communication, navigation, and remote sensing applications treated in this book range all the way from extremely low frequencies (ELF) to microwaves.

Exact ULF/ELF dipole field strengths in the Earth‐ionosphere cavity over the Schumann resonance region: Idealized boundaries

“…Tripathi et al [1982] and Galejs [1971] showed that traversal of the signal through the lower ionosphere allows a HED source to excite the waveguide (TM0) mode. Likewise, Wait [1962] …”

On the Radiation From a Short Current-Carrying Straight Wire Oriented Perpendicular to a Stratified Medium

“…Despite the number of contributions from researchers, to date accurate analytical expressions for the fields, valid regardless of the operating frequency, can be derived only under the assumption that both the source and the observation points lie on the surface of the material medium [10,23]. If this condition cannot be met, closed-form expressions for the fields may still be obtained, but at the price of introducing approximations that limit their applicability to electrically dense media [4][5][6][7]11] or specified frequency ranges [4][5][6][17][18][19][20]. Examples of contributions in this direction are the solutions valid for the quasi-static, indermediate, and far-field frequency ranges, which result from reducing the Sommerfeld integrals to forms amenable to asymptotic techniques such as the saddle-point method [13,[17][18][19][20].…”

“…The study of the radiation characteristics of dipole antennas situated in proximity to stratified media has attracted the interest of several scientists in the past years [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. This is because electric dipoles are extensively used in a variety of engineering applications, especially in the areas of close-to-thesurface radio communication, geophysical prospecting, radio remote sensing, and hypethermia [2-7, 11-15, 22, 23].…”

Surface Parameter Estimation Using Bistatic Polarimetric X-Band Measurements

“…However, it is necessary for the calculation of the interferometric phase to consider not only the soil moisture but also gradients of the water contents in the soil, considering the very large sensitivity of the phase to the values of these gradients. Thus, to analyze the signal phase of a wave scattered by a smooth surface, the method of the layers [34], allows the exact calculation of the phase, which depends on all the values of the complex dielectric constant up to the penetration depth. The remote sensing observation depth is defined as the depth of soil where the soil moisture can be estimated or where the microwave radar is sufficiently sensitive.…”

“…Nevertheless in the specular case, the wave undergoes with a greater probability coherent scattering on the surface, where the dielectric contrast is too high [33]. For the coherent scattering, the phase shift is deterministic and it is given by the formula of coherent scattering on laminated mediums approximated by the Wentzel-Kramer-Brillouin (WKB) model [34]. Outside of the specular direction, the random fluctuations of the phase are increased by the effect of the volume scattering: this effect is valid also for a smooth plane surfaces and rough surface smaller than the macroscopic roughness.…”