摘要:

A review of the theory of electromagnetic wave propagation along a system of horizontal wires in a layered medium is given. Numerical results for the propagation constants of a variety of specific structures are presented and examined as functions of wire and medium parameters. The full modal description of such structures is discussed, and its relation to excitation by specific sources is examined. Finally, a brief assessment of currently outstanding problems in this area is given.

ISSN:0272-6343    

DOI:10.1080/02726348108915134

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

One type of cable being considered for direct buried use in the SEAFARER ELF transmitting system has a tubular metallic shield covered with an insulating jacket which surrounds the insulated main current carrying conductor. An analytical model is developed to predict the induced currents and potentials and impedance loading effects of such a cable shield segmented by circumferential gaps. We first set up the EM field equations and solve the boundary value problem to obtain two modes of propagation on such a cable buried at great depth. The shield segments may be grounded at either end or both. By applying terminal conditions at the source end and load end of a segment, the current and potential distributions and impedance seen by the source are calculated. With this type of shielded cable, gaps in the shield are needed only at intervals of several miles to limit the incremental resistance added by the shield to less than a percent. Comparisons are shown between the theoretical calculations and experimental observations on buried cables at the U.S. Navy Wisconsin Test Facility.

ISSN:0272-6343    

DOI:10.1080/02726348108915135

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Effective numerical methods for solving simple integral and integro-differential equations with logarithmically singular kernels are presented tutorially in this paper. Fundamental features and interrelationships of the methods are discussed. Procedures for applying the techniques to practical equations of electromagnetics are suggested.

ISSN:0272-6343    

DOI:10.1080/02726348108915136

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Using an axisymmetric inhomogeneous lossy dielectric model of the human cranial structure, calculations yielding interior absorbed power density spatial distributions and whole-body cross sections are presented. These computations are performed by way of a finite element implementation of the coupled azimuthal potential formulation. Results are considered for two angles of plane wave incidence, with two orthogonal polarizations, at the frequencies of 1 GHz and 3 GHz. Comparisons are made with a simpler multi-layered spherical model. Attention is given to the sensitivity of “hot spot” intensities to incident field orientations and model parameter uncertainties.

ISSN:0272-6343    

DOI:10.1080/02726348108915137

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

A systematic procedure is presented for computing the electromagnetic scattering by two arbitrarily oriented bodies of revolution when the size of the objects are in the resonance region. The analysis uses a System Transfer Operator (T-matrix) approach and iteratively solves for the scattering of the two-body configuration. A modified unimoment technique is employed to generate the system transfer matrix of each body of revolution. Results are presented and compared to measured data to demonstrate the versatility and accuracy of the analysis. Applications of the two-body analysis stem from extending it to N-bodies. Some potential applications are discussed along with the major problems that need to be addressed.

ISSN:0272-6343    

DOI:10.1080/02726348108915138

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor