摘要:

The issues associated with the choice of.coupling coefficient forms in the singularity expansion and the closely-related subject of whether expansions may be written without an entire function present have persisted as major points of concern and confusion in the development of singularity expansion method theory. In this paper we show that the variety of choices available to one in constructing a singularity expansion relates directly to the large-s asymptotic behavior of the resolvent kernel for the integral equation from which the expansion is derived. The choices range from a cautious extreme in which causality is enforced explicitly to a bold extreme where one depends upon the expansion to sum to a causal result well ahead of the time of arrival of the excitation. By appealing to recently-reported estimates of this asymptotic behavior we define what the acceptable constructions are and discuss them on a comparative basis. A geometrical interpretation of the domain of integration for specific useful choices is provided. It is shown that one may choose the so-called turn-on time outside the acceptable range of choices, but at the expense of including an entire function contribution in the representation. The contribution of this entire function is generally significant enough that it cannot be neglected. It is shown, too, that the ordering of the pole series so that all poles associated with a given eigenvalue of the integral operator are grouped can admit to a choice of a bold coupling coefficient construction. The practicality of this eigenset summation, however, is questionable since the availability of eigenset information hinges on the separability of Maxwell's equations for a particular object shape and since for all but simply rotationally symmetric shapes the pole series may require augmentation by a branch integral for a given eigenvalue. An appendix is provided illustrating a number of the points made in the body of the paper for the simple example of a voltage wave excited on a uniform lossless transmission line.

ISSN:0272-6343    

DOI:10.1080/02726348208915164

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

It has been pointed out by several workers that the class 1 coupling coefficient form of the SEM expansion for the current density on a scattering object tends to be numerically unstable in the early time, before the leading edge of the incident field clears the object. The class 1 form is computationally more attractive than the more reliable class 2 form; it is also the form mandated in some applications as, for example, in the SEM equivalent circuit synthesis. This paper presents a numerical evidence that the class 1 coupling coefficient form yields good results provided the time origin of the problem is placed at the observation point. It is concluded that the assessment of the practical utility of the class 1 coupling coefficient form prevailing in the literature is, perhaps, too pessimistic.

ISSN:0272-6343    

DOI:10.1080/02726348208915165

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

A general solution describing electromagnetic wave propagation alone a transmission line periodically loaded with varactor diodes, with arbitrary terminal impedances, is obtained up to 3rd order in the frame of the Volterra functional method. Forward phase-matched 2nd harmonic generation with matched generator and load impedances is treated in detail. Design curves are given.

ISSN:0272-6343    

DOI:10.1080/02726348208915166

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The Fourier spectra of the fields from a uniformly moving harmonic source are investigated. These spectra are found as space integrals of a dyadic Green's function multiplied with the source current density. The spectra turn out to be bandlimited and to evidence two (infinite) peaks. The analysis is valid for arbitrary velocities and for arbitrary distances between the source volume and the observation point. The spectra of the fields from a moving dipole are treated in some detail.

ISSN:0272-6343    

DOI:10.1080/02726348208915167

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

A theory of intensity scattering from a multi-layered random medium with irregular boundaries is developed using the radiative transfer formulation. Explicit forms for the zeroth and first-order solutions are given. Special cases are shown and compared with previous results. The similarities and differences between the results of this and previous studies are pointed out. In particular, terms omitted in previous studies are indicated and previous scalar or partially scalar formulations are generalized to permit a complete polarization treatment.

ISSN:0272-6343    

DOI:10.1080/02726348208915168

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor