| 1. |
- Engström, Christian, et al.
(författare)
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Homogenization of the Maxwell equations using Floquet-Bloch decomposition
- 2003
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Ingår i: Mathematical and numerical waves 2003. - Berlin, Heidelberg : Springer. - 9783642558566 - 354040127X ; , s. 412-416
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Konferensbidrag (refereegranskat)abstract
- Using Bloch waves to represent the full solution of the Maxwell equations inperiodic media, we study the limit process where the material's period becomes much smaller than the wavelenght. it is seen that effective material parameters can be extracted and explicity represented in terms of the non-vanishing Bloch waves, providing an alternative means of homogenization.
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| 2. |
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| 3. |
- Gustavsson, Magnus, et al.
(författare)
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Multiple scattering by a collection of randomly located obstacles - numerical implementation of the coherent fields
- 2016
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Ingår i: Journal of Quantitative Spectroscopy & Radiative Transfer. - : Elsevier BV. - 0022-4073. ; 185, s. 95-100
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Tidskriftsartikel (refereegranskat)abstract
- A numerical implementation of a method to analyze scattering by randomly located obstacles in a slab geometry is presented. In general, the obstacles can be of arbitrary shape, but, in this first implementation, the obstacles are dielectric spheres. The coherent part of the reflected and transmitted intensity at normal incidence is treated. Excellent agreement with numerical results found in the literature of the effective wave number is obtained. Moreover, comparisons with the results of the Bouguer–Beer (B–B) law are made. The present theory also gives a small reflected coherent field, which is not predicted by the Bouguer–Beer law, and these results are discussed in some detail.
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| 4. |
- Gustavsson, Magnus, et al.
(författare)
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Multiple scattering by a collection of randomly located obstacles Part II: Numerical implementation - coherent fields
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A numerical implementation of a rigorous theory to analyze scattering by randomly located obstacles is presented. In general, the obstacles can be of quite arbitrary shape, but, in this first implementation, the obstacles are dielectric spheres. The coherent part of the reflected and transmitted intensity at normal incidence is treated. Excellent agreement with numerical results found in the literature of the effective wave number is obtained. Moreover, comparisons with the results of the Radiative Transfer Equation (RTE) are made. The present theory also gives a small reflected coherent field, which is not predicted by the RTE, and these results are discussed in some detail.
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| 5. |
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| 6. |
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| 7. |
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| 8. |
- Kristensson, Gerhard, et al.
(författare)
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Multiple scattering by a collection of randomly located obstacles distributed in a dielectric slab
- 2018
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Ingår i: Bremen Workshop on Light Scattering 2018.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Scattering of electromagnetic waves by discrete, randomly distributed objects inside a (finite or semi-infinite) slab is addressed. In general, the non-intersecting scattering objects can be of arbitrary form, material and shape with number density n0 (number of scatterers per volume). The main aim of this paper is to calculate the coherent reflection and transmission characteristics for this configuration. Typical applications of the results are found at a wide range of frequencies (radar up to optics), such as attenuation of electromagnetic propagation in rain, fog, and clouds etc. The integral representation constitutes the underlying framework of the solution of the deterministic problem, which then serves as the starting point for the solution of the stochastic problem. Conditional averaging and the employment of the Quasi Crystalline Approximation lead to a system of integral equations in the unknown expansion coefficients. The slab geometry implies a system of integral equations in the depth variable. Explicit solutions for tenuous media and low frequency approximations can be obtained for spherical obstacles.
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| 9. |
- Kristensson, Gerhard, et al.
(författare)
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Multiple scattering by a collection of randomly located obstacles distributed in a dielectric slab
- 2020
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Ingår i: Advances in Mathematical Methods for Electromagnetics. - : Institution of Engineering and Technology. - 9781785613845 - 9781785613852 ; , s. 621-651
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Bokkapitel (refereegranskat)abstract
- Multiple scattering of electromagnetic waves by a discrete collection of scatterers is a well-studied subject, and many excellent treatments are found in the literature. The deterministic analysis of the scattering problem in this chapter is an extension of the problems treated previosly. Moreover, the present analysis generalizes the established results in two previous papers to a geometry with a more general background material, which is practical for a controlled experimental verification of the final result. The transmitted and reflected intensities are conveniently represented as a sum of two terms-the coherent and the incoherent contribution. In this chapter, we focus on the analysis of the coherent term. The chapter is organized as follows. In Section 25.2, the geometry of the multiple electromagnetic scattering problem is given, and in Section 25.3, the main tool to solve the problem-the integral representation-is introduced. The integral representations are exploited in the various homogeneous regions of the problem in Section 25.4, and the appropriate expansions of the surface fields are introduced in Section 25.5. The final goal of the chapter is to calculate the transmitted and reflected coherent fields of the problem.
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| 10. |
- Kristensson, Gerhard, et al.
(författare)
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Multiple scattering by a collection of randomly located obstacles Part III: Theory - slab geometry
- 2017
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In this paper, scattering of electromagnetic waves by discrete, randomly distributed objects inside a (finite thickness or semi-infinite) slab is addressed.In general, the non-intersecting scattering objects can be of arbitrary form, material and shape with a number density of $n_0$ (number of scatterers per volume).The main aim of this paper is to calculate the coherent reflection and transmission characteristics for this configuration.Applications of the results are found at a wide range of frequencies (radar up to optics), such as attenuation of electromagnetic propagation in rain, fog, and clouds etc. The integral representation of the solution of the deterministic problem constitutes the underlying framework of the stochastic problem.Conditional averaging and the employment of the Quasi Crystalline Approximation lead to a system of integral equations in the unknown expansion coefficients. With a uniform distribution of scatterers the analysis simplifies to a system of integral equations in the depth variable. Explicit solutions for tenuous media and low frequency approximations can be obtained for spherical obstacles.
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