Generalized Fourier Transform for Stratified Media

1972 ◽  
Vol 50 (24) ◽  
pp. 3123-3131 ◽  
Author(s):  
E. Bahar
Keyword(s):  
Electromagnetic Theory ◽  
Observation Point ◽  
Propagation Path ◽  
Stratified Media ◽  
Generalized Fourier Transform ◽  
Scalar Wave ◽  
Exact Boundary ◽  
Impedance Condition ◽  
Fourier Type ◽  
Infinite Media

A Fourier-type transform is derived for functions satisfying the scalar wave equation in stratified media. Using this transform, the function is expressed as a sum of two infinite integrals and a discrete term. In electromagnetic theory, the infinite integrals correspond to the radiation and the lateral wave terms and the discrete term corresponds to the surface wave.The transform provides a suitable basis for the expansion of electromagnetic fields when the height of the interface between two semi-infinite media and their electromagnetic parameters vary along the propagation path. Exact boundary conditions are employed here rather than the restricted surface impedance condition. The expansion is particularly appropriate for problems in which the source and the observation point are not in the same medium.

On an initial boundary value problem involving Beltrami-Moses fields in electromagnetic theory

1993 ◽  
Vol 344 (1671) ◽  
pp. 235-248 ◽  
Keyword(s):  
Boundary Value Problem ◽  
Boundary Value ◽  
Initial Boundary ◽  
Initial Boundary Value Problem ◽  
Electromagnetic Theory ◽  
Time Dependent ◽  
Covariant Formulation ◽  
Beltrami Fields ◽  
Initial Boundary Value ◽  
Infinite Media

The so-called Harmuth ansatz consists of including autonomous magnetic sources in the time-dependent Maxwell postulates. The Beltrami fields are eigenfunctions of the curl operator, and have been used by Moses for propagation in infinite media. These developments are of relatively recent provenances in electromagnetic theory. We discuss an initial-boundary value problem (IBVP) within the framework of a manifestly covariant electromagnetic formalism by using the Harmuth ansatz. We also show how a covariant formulation of the Beltrami-Moses fields may be used for solving electromagnetic IBVPS.

Scattering and depolarization of electromagnetic waves in irregular stratified spheroidal structures of finite conductivity – full wave analysis

1983 ◽  
Vol 61 (1) ◽  
pp. 128-139 ◽  
Author(s):  
E. Bahar ◽  
M. Fitzwater
Keyword(s):  
Electromagnetic Waves ◽  
Radial Distance ◽  
Electromagnetic Theory ◽  
Finite Conductivity ◽  
Wave Analysis ◽  
Bodies Of Revolution ◽  
First Order ◽  
Full Wave ◽  
Exact Boundary ◽  
Full Wave Analysis

Scattering and depolarization of electromagnetic waves in irregular stratified, spheroidal structures (bodies of revolution) are investigated. Using complete expansions for the electromagnetic fields, Maxwell's equations are converted into sets of first order coupled differential equations for the forward and backward wave amplitudes. To obtain these generalized telegraphists' equations, exact boundary conditions are imposed at each of the interfaces between the irregular layers of the structure and Green's theorems are used to avoid term-by-term differentiation of the complete expansions. The electromagnetic parameters of the medium are assumed to vary as functions of the radial distance and the latitude. Excitations by arbitrary distributions of electric and magnetic sources are considered. Thus, this work can be applied to propagation in irregular ionospheric and tropospheric ducts. The solutions are shown to satisfy duality and reciprocity relationships in electromagnetic theory.

Radio Wave Propagation in Stratified Media with Nonuniform Boundaries and Varying Electromagnetic Parameters: Full Wave Analysis

1972 ◽  
Vol 50 (24) ◽  
pp. 3132-3142 ◽  
Author(s):  
E. Bahar
Keyword(s):  
Wave Propagation ◽  
Radio Wave ◽  
Travelling Waves ◽  
Radio Wave Propagation ◽  
Stratified Media ◽  
Electromagnetic Parameters ◽  
Full Wave ◽  
Exact Boundary ◽  
Full Wave Analysis ◽  
Discrete Part

Full wave solutions are derived to the problem of radio wave propagation in stratified media with non-uniform boundaries and varying electromagnetic parameters. The analysis employs a complete set of forward and backward travelling waves. The continuous parts of the wavenumber spectrum constitute the radiation field and the lateral waves, and the discrete part of the spectrum is identified as the surface wave term. The solutions are not restricted by the approximate surface impedance concept and the source and receiver can be situated on opposite sides of the interface. Exact boundary conditions are imposed and the solutions are shown to be consistent with the reciprocity relationships.

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