Design of Coating Materials for Cloaking and Directivity Enhancement of Cylindrical Antennas Using Transformation Optics

Keivaan, Ali; Fakheri, Mohammad Hosein; Abdolali, Ali; Oraizi, Homayoon

doi:10.1109/lawp.2017.2764064

Cited by 22 publications

(13 citation statements)

References 23 publications

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“…The effect of general coordinate transformations on Maxwell's equations is well known, and their applications have been proposed for example for cloaking [15], antenna pattern manipulation [16] and geometry deformation for efficient analysis of elliptical structures [17,18], to cite just a few. Often, these approaches are labelled 'transformation optics' [19] or 'transformation electromagnetics' [20].…”

Section: Coordinate Transformationsmentioning

confidence: 99%

Exact conic section arc elements in 2D and 2.5D FEM using a coordinate transformation

Codecasa

Gentili

Khosronejad

et al. 2021

IET Microwaves Antenna & Prop

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This study introduces the conic section arc elements in 2D and 2.5D finite element method (FEM ). Elements are obtained by deforming an edge in a standard triangular element through a coordinate transformation. This allows to completely eliminate the geometrical error in structures composed of circular, elliptical, hyperbolic and parabolic arcs. The element order is defined independently of the geometrical description of the boundary, allowing the use of simple meshers. Previously available FEM codes can be straightforwardly modified to introduce the conic section boundaries.This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

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Section: Coordinate Transformationsmentioning

confidence: 99%

Exact conic section arc elements in 2D and 2.5D FEM using a coordinate transformation

Codecasa

Gentili

Khosronejad

et al. 2021

IET Microwaves Antenna & Prop

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“…As the obtained material parameters have a narrower range of permittivity and permeability, it could become more experimentally realizable in two-and three-dimensions [14][15][16]. "Unidirectional cloaks" with promising features of cloaking the objects in free space, while having realizable material parameters are presented in [17][18][19][20][21]. In this type of invisibility cloak, a part of space is transformed into an infinitesimal PEC surface.…”

Section: Introductionmentioning

confidence: 99%

“…The proposed structure in [21] has the merit of simultaneously achieving both the cloaking and directivity enhancement for a cylindrical antenna. However, the realization of complex anisotropic and inhomogeneous media is difficult.…”

Section: Introductionmentioning

confidence: 99%

Bi-Functional Antenna Coating for Cloaking and Directivity Enhancement Made of Isotropic Materials

Fakheri¹,

Abdolali²,

Moradinia³

et al. 2020

PIER M

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In this paper, using quasi-conformal mapping, a bi-functional coating layer is designed with the intention of both cloaking and directivity enhancement of an omnidirectional antenna. For TM external waves coming from a certain direction, the proposed coating layer conceals the inner objects. In addition to the cloaking performance, the designed coating layer plays the role of a metamaterial-based lens that dramatically enhances the directivity level of inner omnidirectional loopfamily antennas. To reach this goal, a proper coordinate transformation is elaborately utilized to transform the cylindrical wavefronts radiated from the antenna into semi-pure plane waves. With appropriate simplifications, the proposed coating layer turns into an isotropic meta-device, which is more suitable to be fabricated. To prove the feasibility of the implementation, an SRR-meander line meta-atom is designed to locally realize the required permittivity and permeability distribution of the bi-functional layer. Full-wave simulations are performed via COMSOL finite element solver to validate the cloaking effect and directivity enhancement of the proposed coating layer, at the same time.

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“…BoR-FEM can be used for elliptical structures thanks to a coordinate transformation, also named “Transformation Optics” (TO), or “Transformation Electromagnetics”, a rather new approach to electromagnetic design [6]. In the literature, TO has been exploited for different scopes, such as antenna design [6–9], cloaking, or pattern manipulation [10–14]. In this work and in [5] we adopt it with a different point of view, since we use TO as a tool to convert the original geometry to a shape suitable to be modeled by BoR-FEM, with huge savings in terms of memory allocation and CPU-time.…”

Section: Introductionmentioning

confidence: 99%

Analysis of elliptical structures with constant axial ratio by Body-of-Revolution Finite Element Method and Transformation Optics

Gentili

Khosronejad

Pelosi

et al. 2019

Int. J. Microw. Wireless Technol.

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Design of Coating Materials for Cloaking and Directivity Enhancement of Cylindrical Antennas Using Transformation Optics

Cited by 22 publications

References 23 publications

Exact conic section arc elements in 2D and 2.5D FEM using a coordinate transformation

Exact conic section arc elements in 2D and 2.5D FEM using a coordinate transformation

Bi-Functional Antenna Coating for Cloaking and Directivity Enhancement Made of Isotropic Materials

Analysis of elliptical structures with constant axial ratio by Body-of-Revolution Finite Element Method and Transformation Optics

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