Optical Theorem and Forward Scattering Sum Rule for Periodic Structures

Gustafsson, Mats; Vakili, Iman; Keskin, Sinem; Sjöberg, Daniel; Larsson, Christer

doi:10.1109/tap.2012.2201113

Cited by 30 publications

(30 citation statements)

References 39 publications

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“…Sum rules have been used to derive physical bounds on electromagnetic systems such as matching [23], radar absorbers and array antennas [22,75,94], antennas [33,43,44], scattering [34,103], high-impedance surfaces [49], and metamaterials [41,52,104]. The sum rules are integral identities that often relate the parameter of interest integrated over all frequencies with some low-frequency quantity.…”

Section: Sum Rulesmentioning

confidence: 99%

Physical Bounds of Antennas

Gustafsson¹,

Tayli²,

Cismasu³

2016

Handbook of Antenna Technologies

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Design of small antennas is challenging because fundamental physics limits the performance. Physical bounds provide basic restrictions on the antenna performance solely expressed in the available antenna design space. These limits offer antenna designers a-priori information about the feasibility of antenna designs and a figure of merit for different designs. Here, an overview of physical bounds on antennas and the development from circumscribing spheres to arbitrary shaped regions and embedded antennas are presented. The underlying assumptions for the methods based on circuit models, mode expansions, forward scattering, and current optimization are illustrated and their pros and cons are discussed. The physical bounds are compared with numerical data for several antennas.

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Section: Sum Rulesmentioning

confidence: 99%

Physical Bounds of Antennas

Gustafsson¹,

Tayli²,

Cismasu³

2016

Handbook of Antenna Technologies

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“…Thus, these restrictions are not applicable for the proposed lossy structure lacking a ground plane. The limitations on periodical arrays [7] concern only the transmission properties. Obviously, exploitation of the opportunity to design a resonant absorber, which is transparent outside of the absorption band, could open up a number of novel possibilities in applications, for example, in ultrathin filters for wave trapping, selective multifrequency bolometers, and sensors.…”

Section: Introductionmentioning

confidence: 99%

Broadband Reflectionless Metasheets: Frequency-Selective Transmission and Perfect Absorption

et al. 2015

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Energy of propagating electromagnetic waves can be fully absorbed in a thin lossy layer, but only in a narrow frequency band, as follows from the causality principle. On the other hand, it appears that there are no fundamental limitations on broadband matching of thin resonant absorbing layers. However, known thin absorbers produce significant reflections outside of the resonant absorption band. In this paper, we explore possibilities to realize a thin absorbing layer that produces no reflected waves in a very wide frequency range, while the transmission coefficient has a narrow peak of full absorption. Here we show, both theoretically and experimentally, that a thin resonant absorber, invisible in reflection in a very wide frequency range, can be realized if one and the same resonant mode of the absorbing array unit cells is utilized to create both electric and magnetic responses. We test this concept using chiral particles in each unit cell, arranged in a periodic planar racemic array, utilizing chirality coupling in each unit cell but compensating the field coupling at the macroscopic level. We prove that the concept and the proposed realization approach also can be used to create nonreflecting layers for full control of transmitted fields. Our results can have a broad range of potential applications over the entire electromagnetic spectrum including, for example, perfect ultracompact wave filters and selective multifrequency sensors.

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“…This fundamental result of wave theory has been the topic of a large body of literature in the past 15 years, which has addressed, among other areas, generalizations to arbitrary probing fields and media [3][4][5], detailed accounts for nonhomogeneous media [6,7], descriptions from the point of view of Green's function extraction from field correlations [8,9], and Green-operator-based optical theorem formulations [10]. Other contributions include formulations of the optical theorem for specialized sensing geometries and coordinate systems [11][12][13], the optical theorem for active scatterers [14], as well as applications to periodic structures [15], sensors [16], lasers [17], and computational methods [18]. The vast majority of the past efforts in this area have focused on the frequency domain formulation relevant to linear time-invariant (LTI) media.…”

Section: Introductionmentioning

confidence: 99%

Generalized Optical Theorem in the Time Domain

Marengo¹,

Tu²

2016

PIER B

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Abstract-The optical theorem is a fundamental result that describes the energy budget of wave scattering phenomena. Most past formulations have been derived in the frequency domain and thus apply only to linear time-invariant (LTI) scatterers and background media. In this paper we develop a new theory of the electromagnetic form of the optical theorem directly in the time domain. The derived formulation covers not only the ordinary optical theorem but also the most general form of this result, known as the generalized optical theorem. The developed formulation provides a very general description of the optical theorem for arbitrary probing fields and general scatterers that can be electromagnetically nonlinear, time-varying, and lossy. In the derived formalism, both the scatterer and the background medium can be nonhomogeneous and anisotropic, but the background is assumed to be LTI and lossless. The derived results are illustrated with a computer simulation study of scattering in the presence of a corner reflector which acts as the background. Connections to prior work on the time-domain optical theorem under plane wave excitation in free space are also discussed.

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Optical Theorem and Forward Scattering Sum Rule for Periodic Structures

Cited by 30 publications

References 39 publications

Physical Bounds of Antennas

Physical Bounds of Antennas

Broadband Reflectionless Metasheets: Frequency-Selective Transmission and Perfect Absorption

Generalized Optical Theorem in the Time Domain

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