| 1. |
- Fridén, Jonas, et al.
(författare)
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Effect of dissipation on the constitutive relations of bi-anisotropic media - the optical response
- 1997
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Ingår i: Electromagnetics. - : Informa UK Limited. - 0272-6343 .- 1532-527X. ; 17:3, s. 251-267, s. 125-128
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Tidskriftsartikel (refereegranskat)abstract
- This paper discusses the restrictions that dissipation forces on the material parameters and responses of bi-anisotropic media. The treatment is a general time domain analysis where six-vector formalism is applied. Energy conditions set limitations on the optical response dyadics and dyadic susceptibility kernels of the material that have to be satisfied regardless the time dependence of the fields. This paper will treat in detail the resulting restrictions for the optical response of bi-anisotropic media. Examples are given for some special cases. Also uniqueness and equivalence aspects of constitutive relations in the time domain are discussed.
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| 2. |
- Fridén, Jonas, et al.
(författare)
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Effect of dissipation on the constitutive relations of bi-anisotropic media - the optical response
- 1996
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This paper discusses the restrictions that dissipation forces on the material parameters and responses of bi-anisotropic media. The treatment is a general time domain analysis where six-vector formalism is applied. Energy conditions set limitations on the optical response dyadics and dyadic susceptibility kernels of the material that have to be satisfied regardless the time dependence of the fields. This paper will treat in detail the resulting restrictions for the optical response of bi-anisotropic media. Examples are given for some special cases. Also uniqueness and equivalence aspects of constitutive relations in the time domain are discussed.
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| 3. |
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| 4. |
- Kristensson, Gerhard, et al.
(författare)
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Mixing formulas in time domain
- 1998
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Ingår i: Journal of the Optical Society of America A. - 1084-7529. ; 15:5, s. 1411-1422
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Tidskriftsartikel (refereegranskat)abstract
- The dispersive properties of dielectric materials in both the time and the frequency domains are discussed. Special emphasis is placed on the treatment of heterogeneous materials, particularly two-phase mixtures. A time-domain Maxwell-Garnett rule is derived that differs from the corresponding frequency-domain formula in that it is expressed in terms of convolutions and inverse operators of the susceptibility kernels of the materials. Much of the analysis deals with the question of how the temporal dispersion of the dielectric responses of various physical materials is affected by the mixing process. Debye, Lorentz, Drude, and modified Debye susceptibility models are treated in detail.
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| 5. |
- Kristensson, Gerhard, et al.
(författare)
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Mixing formulas in time domain
- 1997
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This paper discusses the dispersive properties of dielectric materials both in the time and the frequency domains. Special emphasis is on the treatment of heterogeneous materials, in particular two-phase mixtures. A time domain Maxwell Garnett rule is derived which differs from the corresponding frequency domain formula in the respect that it is expressed in terms of convolutions and inverse operators of the susceptibility kernels of the materials. Much of the analysis deals with the question how the temporal dispersion of the dielectric response of various physical materials is affected by the mixing process. Debye, Lorentz, Drude, and modified Debye susceptibility models are treated in detail.
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| 6. |
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| 7. |
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| 8. |
- Sihvola, Ari
(författare)
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Homogenization of a dielectric mixture with anisotropic spheres in anisotropic background
- 1997
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Ingår i: Electromagnetics. - : Informa UK Limited. - 0272-6343 .- 1532-527X. ; 17:3, s. 269-285
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Tidskriftsartikel (refereegranskat)abstract
- This paper treats the problem of calculating the macroscopic effective properties of dielectric mixtures where both the inclusions and the background medium can be anisotropic. For this homogenization process, the Maxwell Garnett -type approach is used where the inclusions are assumed to be spherical and embedded in a homogeneous background medium. The anisotropy of the background medium has to be described with a symmetric permittivity dyadic but the inclusion may be fully anisotropic, in other words the inclusion permittivity dyadic can contain an antisymmetric component. The effect of the anisotropy of the background is such that the depolarization factors of the spheres become different in different directions, even if the geometry is isotropic. This effect has to be taken into account for the calculation of the polarizability dyadic. As an example, numerical values are calculated for the case of gyrotropic spheres in anisotropic environment, both for the polarizability and effective permittivity dyadics. Finally, some thoughts are raised concerning the physical interpretation of the anisotropy effect, as well as the reciprocity of the materials and symmetry of their permittivities.
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| 9. |
- Sihvola, Ari
(författare)
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Homogenization of a dielectric mixture with anisotropic spheres in anisotropic background
- 1996
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This paper treats the problem of calculating the macroscopic effective properties of dielectric mixtures where both the inclusions and the background medium can be anisotropic. For this homogenization process, the Maxwell Garnett -type approach is used where the inclusions are assumed to be spherical and embedded in a homogeneous background medium. The anisotropy of the background medium has to be described with a symmetric permittivity dyadic but the inclusion may be fully anisotropic, in other words the inclusion permittivity dyadic can contain an antisymmetric component. The effect of the anisotropy of the background is such that the depolarization factors of the spheres become different in different directions, even if the geometry is isotropic. This effect has to be taken into account for the calculation of the polarizability dyadic. As an example, numerical values are calculated for the case of gyrotropic spheres in anisotropic environment, both for the polarizability and effective permittivity dyadics. Finally, some thoughts are raised concerning the physical interpretation of the anisotropy effect, as well as the reciprocity of the materials and symmetry of their permittivities.
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| 10. |
- Sihvola, Ari, et al.
(författare)
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Non-radiating sources in time-domain transmission-line theory
- 1997
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Ingår i: IEEE Transactions on Microwave Theory and Techniques. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9480. ; 45:12 Part 1, s. 2155-2159
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Tidskriftsartikel (refereegranskat)abstract
- The concept of nonradiating (NR) sources is introduced to transmission lines in the time-domain analysis. A method is presented to construct localized voltage and current sources which do not produce any fields outside the source domain. These sources cannot, therefore, be detected by measurements made outside the source region. The importance of such sources for the uniqueness of the inverse-source problem is pointed out, and energy conditions for the uniqueness are discussed. The analysis can be advantageously used in the design and optimization of the electromagnetic compatibility (EMC) properties of transmission lines
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