Modal Expansions and Orthogonal Complements in the Theory of Complex Media Waveguide Excitation by External Sources for Isotropic, Anisotropic, and Bianisotropic Media

Barybin, A. A.

doi:10.2528/pier97120800

Cited by 17 publications

(58 citation statements)

References 19 publications

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“…In analogy with the electric conductivity, a magnetic conductivity tensor can be de ned as σ m = −iωµ 0 µ − µ † /2 [2], although it has units of [σ m ] = Ω/m and not S/m as in the electric case. With the permeability tensor described above and after some algebra, this is found to be (neglecting components parallel to m 0 since they are zero) Thus, in this particular case(β = 0), σ m can be used to represent a magnetic conductivity tensor, which is independent of frequency.…”

Section: From This It Is Seen That If the Bias Eld Is In The Normalmentioning

confidence: 99%

Biased Magnetic Materials in Ram Applications

Ramprecht¹,

Sjöberg²

2007

PIER

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The magnetization of a ferro-or ferri-magnetic material has been modeled with the Landau-Lifshitz-Gilbert (LLG) equation. In this model demagnetization e ects are included. By applying a linearized small signal model of the LLG equation, it was found that the material can be described by an e ective permeability and with the aid of a static external biasing eld, the material can be switched between a Lorentz-like material and a material that exhibits a magnetic conductivity. Furthermore, the re ection coe cient for normally impinging waves on a PEC covered with a ferro/ferri-magnetic material, biased in the normal direction, is calculated. When the material is switched into the resonance mode, we found that there will be two distinct resonance frequencies in the re ection coe cient, one associated with the precession frequency of the magnetization and one associated with the thickness of the layer. The former of these resonance frequencies can be controlled by the bias eld and for a bias eld strength close to the saturation magnetization, where the material starts to exhibit a magnetic conductivity, one can achieve low re ection (around -20 dB) for a quite large bandwidth (more than two decades).

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Section: From This It Is Seen That If the Bias Eld Is In The Normalmentioning

confidence: 99%

Biased Magnetic Materials in Ram Applications

Ramprecht¹,

Sjöberg²

2007

PIER

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“…Neglecting the non-local effects enables the equations of medium motion to be converted into the constitutive relations with frequency-dependent parameters. In other words, such a medium possesses properties of the usual time-dispersive active medium (TDAM) and in this case its electrodynamic properties fully conform to the ordinary anisotropic media examined in [1]. Our subsequent analysis will be based on results obtained there, among them a novel notion of the mode quasi-orthogonality for lossy waveguides (see section 3 of [1]).…”

Section: Introductionmentioning

confidence: 99%

“…This requires revising some problems of guided-wave electrodynamics, in particular, the theory of waveguide excitation by external sources. The guided-wave excitation theory for passive media with isotropic, anisotropic and bianisotropic properties was developed in [1]. Electrodynamic processes in such passive media are fully described by Maxwell's equations and local constitutive relations, the most general form of which is inherent in bianisotropic media (BAM) with frequencydependent constitutive parameters.…”

Section: Introductionmentioning

confidence: 99%

“…Section 2 includes input information about the modal field expansions with separating potential fields to give a physical insight into the nature of the orthogonal complementary fields obtained previously [1]. Since the electrodynamic description of space-dispersive phenomena requires, in addition to Maxwell's equation, special equations of medium motion, section 3 is devoted to consideration of the appropriate equations for three kinds of SDAM.…”

Section: Introductionmentioning

confidence: 99%

“…The objective in writing the paper is to generalize the guided-wave excitation theory developed previously for the waveguiding structures with time-dispersive bianisotropic media [1] to waveguides filled with a generalized (hypothetical) spacedispersive medium which contains all the piezoelectric, ferrimagnetic and plasma phenomena. Section 2 includes input information about the modal field expansions with separating potential fields to give a physical insight into the nature of the orthogonal complementary fields obtained previously [1].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Excitation theory for space-dispersive active media waveguides

Barybin

1999

J. Phys. D: Appl. Phys.

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Abstract.A unified electrodynamic approach to the guided-wave excitation theory is generalized to the waveguiding structures containing a hypothetical space-dispersive medium with drifting charge carriers possessing simultaneously elastic, piezoelectric and magnetic properties. Substantial features of our electrodynamic approach are: (i) the allowance for medium losses and (ii) the separation of potential fields peculiar to the slow quasi-static waves which propagate in such active media independently of the fast electromagnetic waves of curl nature. It is shown that the orthogonal complementary fields appearing inside the external source region are just associated with a contribution of the potential fields inherent in exciting sources. Taking account of medium losses converts the usual orthogonality relation into a novel form called the quasi-orthogonality relation. Development of the mode quasi-orthogonality relation and the equations of mode excitation is based on the generalized reciprocity relation (the extended Lorentz lemma) specially proved for this purpose with allowing for specific properties of the space-dispersive active media and separating the potential fields. The excitation equations turn out to be the same in form whatever waveguide filling, including both the time-dispersive (bianisotropic) and space-dispersive media. Specific properties of such media are reflected in a particular form of the normalizing coefficients for waveguide eigenmodes. It is found that the separation of potential fields reveals the fine structure of interaction between the exciting sources and mode eigenfields: in addition to the exciting currents (bulk and surface) interacting with the curl fields, the exciting charges (bulk and surface) and the double charge (surface dipole) layers appear to interact with the quasi-static potentials and the displacement currents, respectively.

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References

2021

Electromagnetic Metasurfaces

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Modal Expansions and Orthogonal Complements in the Theory of Complex Media Waveguide Excitation by External Sources for Isotropic, Anisotropic, and Bianisotropic Media

Cited by 17 publications

References 19 publications

Biased Magnetic Materials in Ram Applications

Biased Magnetic Materials in Ram Applications

Excitation theory for space-dispersive active media waveguides

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