Propagation in Irregular Multilayered Cylindrical Structures of Finite Conductivity—Full Wave Solutions

Abstract

Radio wave propagation problems, in irregular multilayered cylindrical structures of finite conductivity, are analyzed. The thickness and the electromagnetic parameters of the layers of the structures are assumed to be functions of the azimuth. Electric and magnetic field transforms consisting of both a discrete and a continuous spectrum of cylindrical waves provide a suitable basis for the expansion of the electromagnetic fields at any point in the unbounded structure.In the analysis, exact boundary conditions are imposed at each interface between the layers of the irregular cylindrical structure and the full wave solutions are shown to satisfy the reciprocity relationships in electromagnetic theory.When the core of the structure is perfectly conducting, the contributions from the continuous part of the wave spectrum vanish. However, in general, when the skin depth of the core is large compared to its dimensions, or when sources are located in the core of the structure and propagation in the core is of particular interest, the electromagnetic fields cannot be expressed exclusively in terms of a discrete spectrum of waves. In these cases, due to the irregularities of the structure, power is continuously coupled between the discrete and continuous constituents of the wave spectrum.