Array Miniaturization Through &lt;italic&gt;QCTO-SI&lt;/italic&gt; Metamaterial Radomes

Oliveri, Giacomo; Bekele, Ephrem T.; Salucci, Marco; Massa, Andrea

doi:10.1109/tap.2015.2434412

Cited by 31 publications

(24 citation statements)

References 33 publications

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“…The focus of the second part of this paper is on the uniqueness of the inverse problem for TO based materials, like invisibility cloaks which usually have anisotropic inhomogeneous constitutive parameters. We show that despite the validity of the uniqueness theorem for the structure, the uniqueness of the inverse problem for the structure is not valid, even though 30 it is valid for a particular anisotropic inhomogeneous structure.…”

Section: Introductionmentioning

confidence: 81%

“…However, this notion is a misunderstanding with uniqueness in an inverse problem. [29][30][31] The focus of this section is on the uniqueness of the inverse problem for TO based materials, like invisibility cloaks. Such materials, usually, have anisotropic inhomogeneous constitutive parameters.…”

Section: On the Uniqueness Of Inverse Electromagnetic Problems Fomentioning

confidence: 99%

“…Even the newer version of TO, called Quasi-Conformal Transformation Optics (QCTO), usually creates materials with diagonal constitutive tensors in various applications including the antenna applications. [29][30][31] The QCTO uses a smoother transformation function to limit anisotropy of the structures. There is a concern regarding the validity of the uniqueness theorem for structures like invisibility cloaks, as these anisotropic inhomogeneous media may support sets of distinct solutions having identical boundary conditions; hence, it might be concluded that the uniqueness theorem may not be valid for such anisotropic inhomogeneous media with diagonal constitutive tensors.…”

Section: Introductionmentioning

confidence: 99%

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Uniqueness theorem and uniqueness of inverse problems for lossy anisotropic inhomogeneous structures with diagonal material tensors

Dehbashi

Bialkowski

Abbosh

2017

Journal of Applied Physics

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The uniqueness theorem for lossy anisotropic inhomogeneous structures with diagonal material tensors is proven. For these materials, we prove that all the elements of the constitutive tensors must be lossy. Materials like cloaks and lenses designed based on transformation-optics (TO) could be examples of such materials. The uniqueness theorem is about the uniqueness of Maxwell's equations solutions for particular sets of boundary conditions. We prove the uniqueness theorem for three cases: Single medium, media composed of two lossy anisotropic inhomogeneous materials with diagonal constitutive parameters, and media composed of two materials, where a material with diagonal material tensors is surrounded by an isotropic material. The latter case can be considered for the TO-based materials like invisibility cloaks or hyper-lenses that usually have diagonal anisotropic inhomogeneous constitutive parameters and also because cloaks or hyper-lenses are usually surrounded by free space and the sources are usually outside. For the sake of our argument in the uniqueness theorem that loss is the main condition for the validity of this theory, for cloaks as an example case of our analysis, it is analytically and numerically proven that the ideal invisibility phenomenon is possible for a simple lossy structure. We also examine the uniqueness of the inverse problem for such structures. We prove that all these materials have the same surface field distribution on a surface enclosing the area of interest, while solutions to Maxwell's equations inside them are different. The uniqueness of the inverse problem suggests that within the surface, the same medium should exactly be present. However, for lossy anisotropic inhomogeneous structures with diagonal constitutive parameters, this paper illustrates that this might not be true, despite the result of a previous study that shows that uniqueness could be true for some anisotropic inhomogeneous structures. For the analysis, the transverse electric Z-polarization is used. The simulation results are obtained by using a commercial Finite-Element based simulator.

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Section: Introductionmentioning

confidence: 81%

Section: On the Uniqueness Of Inverse Electromagnetic Problems Fomentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Uniqueness theorem and uniqueness of inverse problems for lossy anisotropic inhomogeneous structures with diagonal material tensors

Dehbashi

Bialkowski

Abbosh

2017

Journal of Applied Physics

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“…SbD synthesis approach: With reference to the 2D geometry in [9], let us consider a reference L-sized array made of N radiators located in (Fig. 1), affording the electric field distribution E(r) = E z (r) z.…”

mentioning

confidence: 99%

“…. , N ′ } [9]. Unfortunately, such a cascaded QCTO-MA-SI procedure can neither a-priori enforce any upper bound on 1(r ′ ) nor guarantee the best achievable compression ratio (i.e.…”

mentioning

confidence: 99%

System‐by‐design method for efficient linear array miniaturisation through low‐complexity isotropic lenses

et al. 2019

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The design of miniaturised linear arrays by using isotropic lenses with reduced complexity is addressed. The problem at hand is formulated as a global optimisation one, then solved by means of a computationally-efficient customisation of the system-by-design (SbD) paradigm suitably integrated with the quasi-conformal transformation optics method. To yield arbitrary transformation geometries with a limited set of degrees-of-freedom and to reduce the lens complexity, while guaranteeing the same radiation performance of a larger reference aperture, a spline-based description of the lens shape is adopted. Representative numerical results are reported to assess the effectiveness as well as the computational efficiency of the proposed SbD-based approach.

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A Near‐Zero Index Metamaterial Lens for Reduced Complexity and High‐Performance Active Electronically Scanned Arrays

Binion,

Mussman,

Lier

et al. 2024

Adv Elect Materials

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A lens consisting of an anisotropic near‐zero index metamaterial (NZIM) is introduced for improving the far‐field performance of active electronically scanned arrays (AESA). Several simulation studies demonstrate how the NZIM lens (metalens) can be functionalized to transform the embedded element pattern of an array from a typical cosinusoidal shape to a flat‐topped pattern, dramatically reducing the gain at wider angles. This corresponds to reductions in scan loss and suppression of grating lobes in the desired field of view (FOV), especially for arrays with large element spacing (i.e., sparse or thinned arrays). The metalens concept is demonstrated through several simulation studies illustrating the beam shaping capability of NZIM materials. A fabricated metalens demonstrates full suppression of grating lobes and minimal scan loss with a ±10° FOV, which is ideally suited for limited FOV applications such as geosynchronous satellite communications.

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Array Miniaturization Through <italic>QCTO-SI</italic> Metamaterial Radomes

Cited by 31 publications

References 33 publications

Uniqueness theorem and uniqueness of inverse problems for lossy anisotropic inhomogeneous structures with diagonal material tensors

Uniqueness theorem and uniqueness of inverse problems for lossy anisotropic inhomogeneous structures with diagonal material tensors

System‐by‐design method for efficient linear array miniaturisation through low‐complexity isotropic lenses

A Near‐Zero Index Metamaterial Lens for Reduced Complexity and High‐Performance Active Electronically Scanned Arrays

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