Polarization-independent anapole response of a trimer-based dielectric metasurface

Abstract The phenomenon of anapole has attracted considerable attention in the field of metamaterials as a possible realization of radiationless objects. We comprehensively study this phenomenon in the cluster-based systems of dielectric particles by considering conditions of anapole manifestation in both single trimers of disk-shaped particles and metamaterial composed on such trimers. Our analytical approach is based on the multipole decomposition method and the secondary multipole decomposition technique. They allow us to associate the anapole with the multipole moments of the trimer and the separate multipole moments of its constitutive particles. The manifestation of anapole in a two-dimensional metamaterial (metasurface) is confirmed by checking the resonant states in the reflected field as well as from the electromagnetic near-field patterns obtained from the full-wave numerical simulation. It is demonstrated that the anapole excitation in trimers results in the polarization-independent suppression of reflection with the resonant enhancement of local electromagnetic fields in the metasurface. Finally, experimental verification of the theoretical results is presented and discussed.

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Frequency-Diverse Holographic Metasurface Antenna for Near-Field Microwave Computational Imaging

Frontiers in Materials ◽

10.3389/fmats.2021.766889 ◽

2021 ◽

Vol 8 ◽

Author(s):

Jiaqi Han ◽

Long Li ◽

Shuncheng Tian ◽

Xiangjin Ma ◽

Qiang Feng ◽

...

Keyword(s):

Frequency Domain ◽

Imaging System ◽

Near Field ◽

Horn Antenna ◽

Computational Imaging ◽

Simulation Studies ◽

Field Patterns ◽

Full Wave ◽

Imaging Reconstruction ◽

Iterative Shrinkage

This article presents a holographic metasurface antenna with stochastically distributed surface impedance, which produces randomly frequency-diverse radiation patterns. Low mutual coherence electric field patterns generated by the holographic metasurface antenna can cover the K-band from 18 to 26 GHz with 0.1 GHz intervals. By utilizing the frequency-diverse holographic metasurface (FDHM) antenna, we build a near-field microwave computational imaging system based on reflected signals in the frequency domain. A standard horn antenna is adopted to acquire frequency domain signals radiated from the proposed FDHM antenna. A detail imaging restoration process is presented, and the desired targets are correctly reconstructed using the 81 frequency-diverse patterns through full-wave simulation studies. Compressed sensing technique and iterative shrinkage/thresholding algorithms are applied for the imaging reconstruction. The achieved compressive ratio of this computational imaging system on the physical layer is 30:1.

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Analysis of Near-field Measurement Sensors Using Full-Wave Numerical Simulator

2018 International Applied Computational Electromagnetics Society Symposium - China (ACES) ◽

10.23919/acess.2018.8669102 ◽

2018 ◽

Author(s):

Hongxing Zheng ◽

Yong-qiang Sun ◽

Lu Wang

Keyword(s):

Field Measurement ◽

Near Field ◽

Full Wave ◽

Numerical Simulator ◽

Near Field Measurement

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Nonradiative subdiffraction near-field patterns using metagratings

Applied Physics Letters ◽

10.1063/5.0043484 ◽

2021 ◽

Vol 118 (13) ◽

pp. 131105

Author(s):

Oshri Rabinovich ◽

Ariel Epstein

Keyword(s):

Near Field ◽

Field Patterns

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A theoretical and numerical approach for selecting miniaturized antenna topologies on magneto-dielectric substrates

International Journal of Microwave and Wireless Technologies ◽

10.1017/s1759078715000859 ◽

2015 ◽

Vol 7 (3-4) ◽

pp. 369-377 ◽

Cited By ~ 1

Author(s):

Alex Pacini ◽

Alessandra Costanzo ◽

Diego Masotti

Keyword(s):

Near Field ◽

Dielectric Materials ◽

Numerical Approach ◽

Operating Conditions ◽

Microwave Range ◽

Dielectric Substrates ◽

Full Wave ◽

Miniaturized Antenna ◽

Wavelength Radiation ◽

Definition Of

An increasing interest is arising in developing miniaturized antennas in the microwave range. However, even when the adopted antennas dimensions are small compared with the wavelength, radiation performances have to be preserved to keep the system-operating conditions. For this purpose, magneto-dielectric materials are currently exploited as promising substrates, which allows us to reduce antenna dimensions by exploiting both relative permittivity and permeability. In this paper, we address generic antennas in resonant conditions and we develop a general theoretical approach, not based on simplified equivalent models, to establish topologies most suitable for exploiting high permeability and/or high-permittivity substrates, for miniaturization purposes. A novel definition of the region pertaining to the antenna near-field and of the associated field strength is proposed. It is then showed that radiation efficiency and bandwidth can be preserved only by a selected combinations of antenna topologies and substrate characteristics. Indeed, by the proposed independent approach, we confirm that non-dispersive magneto-dielectric materials with relative permeability greater than unit, can be efficiently adopted only by antennas that are mainly represented by equivalent magnetic sources. Conversely, if equivalent electric sources are involved, the antenna performances are significantly degraded. The theoretical results are validated by full-wave numerical simulations of reference topologies.

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Fundamental Analyses on Layered Media Reconstruction Using GPR and Full-Wave Inversion in Near-Field Conditions

IEEE Transactions on Geoscience and Remote Sensing ◽

10.1109/tgrs.2016.2556862 ◽

2016 ◽

Vol 54 (9) ◽

pp. 5143-5158 ◽

Cited By ~ 12

Author(s):

Alberic De Coster ◽

Anh Phuong Tran ◽

Sebastien Lambot

Keyword(s):

Near Field ◽

Layered Media ◽

Field Conditions ◽

Wave Inversion ◽

Full Wave

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A full-wave model for EMI prediction in planar microstrip circuits excited in the near-field of a short electric dipole

IEEE Transactions on Electromagnetic Compatibility ◽

10.1109/15.385881 ◽

1995 ◽

Vol 37 (2) ◽

pp. 175-182 ◽

Cited By ~ 5

Author(s):

P. Bernardi ◽

R. Cicchetti ◽

D.S. Moreolo

Keyword(s):

Electric Dipole ◽

Near Field ◽

Wave Model ◽

Full Wave

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Electromagnetic wave scattering on imperfect cloaking devices

Science of Sintering ◽

10.2298/sos0803245i ◽

2008 ◽

Vol 40 (3) ◽

pp. 245-250

Author(s):

G. Isic ◽

A. Beltaos ◽

R. Gajic ◽

K. Hingerl

Keyword(s):

Electromagnetic Wave ◽

Scattering Theory ◽

Wave Scattering ◽

Singular Values ◽

Shell Material ◽

Electromagnetic Wave Scattering ◽

Material Parameters ◽

Full Wave ◽

Overall Performance ◽

Theoretical Results

Cloaking devices based on the coordinate transform approach enable, in principle, a perfect concealment of a region in space provided that the material composing the cloaking shell meets certain criteria. To achieve ideal cloaking it is necessary that the shell material parameters have singular values on the surface bounding the cloaked region which is unphysical. In this paper we assume finite values of cloak parameters and apply the scattering theory formalism to give an estimate of the overall performance of an 'imperfect' cloak. We perform full-wave numerical calculations and use our theoretical results to discuss them.

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Reconstruction of the near-field distribution in an X-ray waveguide array

Journal of Applied Crystallography ◽

10.1107/s1600576717004630 ◽

2017 ◽

Vol 50 (3) ◽

pp. 701-711 ◽

Cited By ~ 2

Author(s):

Qi Zhong ◽

Lars Melchior ◽

Jichang Peng ◽

Qiushi Huang ◽

Zhanshan Wang ◽

...

Keyword(s):

Layer Thickness ◽

Field Distribution ◽

Phase Retrieval ◽

Near Field ◽

Field Pattern ◽

Waveguide Array ◽

X Ray ◽

Field Patterns ◽

Thickness Variations ◽

Far Field Pattern

Iterative phase retrieval has been used to reconstruct the near-field distribution behind tailored X-ray waveguide arrays, by inversion of the measured far-field pattern recorded under fully coherent conditions. It is thereby shown that multi-waveguide interference can be exploited to control the near-field distribution behind the waveguide exit. This can, for example, serve to create a secondary quasi-focal spot outside the waveguide structure. For this proof of concept, an array of seven planar Ni/C waveguides are used, with precisely varied guiding layer thickness and cladding layer thickness, as fabricated by high-precision magnetron sputtering systems. The controlled thickness variations in the range of 0.2 nm results in a desired phase shift of the different waveguide beams. Two kinds of samples, a one-dimensional waveguide array and periodic waveguide multilayers, were fabricated, each consisting of seven C layers as guiding layers and eight Ni layers as cladding layers. These are shown to yield distinctly different near-field patterns.

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