摘要:

The technique of dyadic Green's function (DGF) expressed in terms of the normalised cylindrical vector wave functions is adopted in this study for examining the electromagnetic fields excited by one thin circular loop antenna above a (un)grounded multi-layered chiral slabs. The current carried on such a circular loop antenna is expressed in a generalized Fourier series so as to incorporate practical situations. Thereby, exact representations of the radiated fields in both near and far zones are obtained in closed form, in a superposition of the right-and left-handed circularly polarized waves. Furthermore, numerical results are presented to show the radiation characteristics of the loop antenna in different layered chiral slab structures. The contributions of the lower- as well as higher-order current excitations to the far-zone field are examined in detail.

ISSN:0920-5071    

DOI:10.1163/156939300X01067

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Green functions corresponding to various polynomial partial differential operators of second, fourth and higher order are derived and the results are collected in tabular form for quick reference. The results and the methods suggested for their derivation are of importance in solving electromagnetic field problems associated with various linear (bi-anisotropic) media.

ISSN:0920-5071    

DOI:10.1163/156939300X01076

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

In this paper, we consider the scattering of an electromagnetic plane wave by an infinite doubly periodic array of slits in a perfectly conducting plane disposed on a grounded lossy dielectric slab. With the increasing sophistication of shielding techniques, we study cracks whose spacing is about some ten micrometers. This paper is devoted to phenomenology of the absorption phenomenon obtained with this complex structure. We show in this paper that doubly periodic cracks combined with a grounded lossy material can become an absorbing structure and ordered slits of 50 μm in a conducting plane permit field penetration. We have manufactured this kind of structure and measured it with a free space technique. We demonstrate in this paper the relevance of our mathematical model based on a Floquet development of the electromagnetic fields within the different layers of the structures and a Galerkin approximation of the surface currents. The agreement between theory and experiments is pretty good and we verify the theoretical prediction of the existence of an absorption band for such a structure.

ISSN:0920-5071    

DOI:10.1163/156939300X01085

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Electromagnetic properties of regular arrays of nonreciprocal inclusions are analytically studied. We consider periodical planar arrays and determine the induced dipole moments in the particles taking into account the field interactions between inclusions. The emphasis is on the energy balance and polarization transformation in the arrays excited by plane normally incident electromagnetic waves. In this case, the scattering from individual inclusions does not lead to any power loss, since only plane waves are reflected and transmitted. We show how this phenomenon is described in terms of the interaction field, and analytically calculate the reflection and transmission coefficients. As an example, polarization transformation properties of arrays of small ferrite spheres are studied and compared with the properties of solid ferrite slabs.

ISSN:0920-5071    

DOI:10.1163/156939300X01094

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

ISSN:0920-5071    

DOI:10.1163/156939300X01102

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor