A Survey on the
                  Low-Dimensional-Model-based
                  Electromagnetic Imaging

Li, Lianlin; Hurtado, Martin; Xu, Feng; Zhang, Bing Chen; Jin, Tian; Cui, Tie Jun; Stevanovic, Marija Nikolic; Nehorai, Arye

doi:10.1561/2000000103

Cited by 21 publications

(19 citation statements)

References 143 publications

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“…In this way, a sequence of quasi-random radiation patterns can be generated by managing the applied voltages of information metasurface, which could provide adequate measurement modes for the high-quality image. For reducing the complexity of controlling the bias voltages of the information metasurface, Li et al proposed that the meta-atoms be manipulated in the column-row-wise manner [84]. Specifically, the information metasurface with N x × N y meta-atoms is controlled by using N x + N y coding sequences.…”

Section: Programmable Imagermentioning

confidence: 99%

“…Specifically, the information metasurface with N x × N y meta-atoms is controlled by using N x + N y coding sequences. More interestingly, they theoretically and experimentally demonstrated that the very simple column-row-wise coding metasurface has a theoretical guarantee to ensure that the required measurement number is comparable to that for the conventional pixel-wise encoded masks, while simultaneously maintaining nearly the same imaging quality [84].…”

Section: Programmable Imagermentioning

confidence: 99%

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Information metamaterials – from effective media to real-time information processing systems

Cui

2019

Nanophotonics

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Metamaterials have been characterized by effective medium parameters over the past decades due to the subwavelength nature of meta-atoms. Once the metamaterials are fabricated, their functions become fixed or tunable. Recently, the concept of digital metamaterials has been introduced, in which, for instance, the constitutive 1-bit meta-atom is digitalized as “0” or “1” corresponding to two opposite electromagnetic (EM) responses. The digital metamaterials set up a bridge between the physical world and the information world. More interestingly, when the digital meta-atom is programmable, a single metamaterial can be used to realize different functions when programmed with different coding sequences. Moreover, as the states of programmable meta-atoms can be quickly switched, it enables the wave-based information coding and processing on the physical level of metamaterials in real time. For these reasons, we prefer to call digital metamaterials with programmable meta-atoms as “information metamaterials.” In this review article, we introduce two basic principles for information metamaterials: Shannon entropy on metamaterials to measure the information capacity quantitatively and digital convolution on metamaterials to manipulate the beam steering. Afterwards, two proof-of-concept imaging systems based on information metamaterials, i.e. programmable hologram and programmable imager, are presented, showing more powerful abilities than the traditional counterparts. Furthermore, we discuss the time-modulated information metamaterial that enables efficient and accurate manipulations of spectral harmonic distributions and brings new physical phenomena such as frequency cloaking and velocity illusion. As a relevant application of time-modulated information metamaterials, we propose a novel architecture of wireless communication, which simplifies the modern wireless communication system. Finally, the future trends of information metamaterials are predicted.

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Section: Programmable Imagermentioning

confidence: 99%

Section: Programmable Imagermentioning

confidence: 99%

Information metamaterials – from effective media to real-time information processing systems

Cui

2019

Nanophotonics

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“…For the conventional imaging technologies, arrays of detectors are required to sense the characters of EM field at the imaging plane. A new cutting‐edge imaging method, single‐sensor imaging, has been proposed and applied in many applications . Only one detecting source is need instead of the source array in the single‐sensor system.…”

Section: Programmable Metamaterialsmentioning

confidence: 99%

“…Programmable metamaterials enable the wave‐based information coding and processing on the physical level of metamaterials in real time. The holograms and image system based on the programmable metamaterials have been proposed and reported . These systems rely on the active and dynamic manipulation of EM waves which push the programmable image systems to have low cost and more flexibility in real applications.…”

Section: Conclusion and Prospectsmentioning

confidence: 99%

Tunable, reconfigurable, and programmable metamaterials

Bao

Cui

2019

Micro & Optical Tech Letters

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Electromagnetic metamaterials have been developing rapidly and attracted worldwide attentions since the concept has been proposed due to their powerful ability in controlling electromagnetic (EM) waves. Active functions and features achieved by tunable or reconfigurable metamaterials are highly desired in the field of science, engineering, and military. With the introduction of digital metamaterials, a bridge between the physical world and the information world is set up. When the digital metamaterials are programmable, they enable the wave‐based information coding and processing on the physical level of metamaterials in real time. In this paper, we will summarize the recent progress on tunable, reconfigurable, and programmable metamaterials. Firstly, we introduce the tunable and reconfigurable metamaterials in terahertz and microwave frequencies. Secondly, we review the functional devices and novel systems by the programmable metamaterials. Finally, we give a brief developing prospect to the programmable metamaterials.

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“…Metasurfaces, the 2D version of MTMs, are drawing more and more attention and have become the new hot spot in the research of MTMs . Governed by the generalized Snell's laws of reflection and refraction, the abrupt phase changes on the interface as well as the surface impedances are modulated so as to realize desired functionalities, such as the manipulating the polarization of EM waves, holographic imaging and transforming wavefronts . It has also been used in the conversion of spatially propagating waves to surfaces waves .…”

Section: Metasurfaces and Other State‐of‐the‐art Microwave Mtmsmentioning

confidence: 99%

Microwave Metamaterials

Chen

Tang

et al. 2019

Annalen der Physik

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Metamaterials (MTMs) are artificial materials composed of subwavelength particles, which are engineered to achieve various electromagnetic (EM) responses. Since the first practical realization and experimental verification of MTMs by Pendry et al. in the late 1990s, great efforts have been made in theoretical study as well as practical utilizations. Among them, the effective medium theory provides a basis for the description as well as an accurate method for the design of MTMs, and leads to the development of many novel devices with interesting functionalities. With the employment of transformation and geometric optics, more high-performance engineering applications have been realized using MTMs. Recently, the concept of metasurfaces has been proposed, which further promotes the practical applications of advanced MTMs. Herein, the effective medium theory is first introduced. After that, typical devices and applications based on conventional bulk MTMs and newly-conceived metasurfaces are summarized to demonstrate the flexible capability of microwave MTMs in the manipulation of EM waves.Metamaterials are different from other periodic structures such as photonic crystals and frequency-selective surfaces (FSSs) because their unit cells are much smaller than the free-space wavelength. The subwavelength nature enables the metamaterials to Tianyi Chen received his B.Sc. degree from Southeast University, Nanjing, China, in 2013. He is currently working toward a Ph.D. degree in State Key Laboratory of Millimeter Waves at Southeast University. His research interests include metamaterials metasurfaces and antenna arrays. Wenxuan Tang received her B.Sc. and M.Sc. degrees from Southeast University, Nanjing, China, in Cheung-Kong Professor. His research interests include metamaterials, plasmonics in microwave, and computational electromagnetics.be treated as a homogenous effective medium and characterized by effective constitutive parameters. In early researches, closed formed expressions for the constitutive parameters were obtained in static and quasistatic limits, [86][87][88] which usually takes the form of Lorentz-Drude models. These results provided some intuition of the physical features but cannot quantitatively characterize metamaterials. In ref.[18], a numerical approach based on scattering (S) parameter retrieval was proposed to obtain the effective permittivity and permeability for periodic metamaterial structures. This method is accurate in the derivation of effective parameters. However it relies on full-wave simulation of metamaterial structures and hence is inefficient and difficult to be used in the design of large-volume metamaterials.In 2007, a general effective medium theory [17] was proposed by Liu et al., which sets up a relationship between particle responses and macroscopic behaviors of metamaterials. A closed form expression was provided to modify the Lorentz-Drude model, which takes the effects of spatial dispersion into account

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A Survey on the Low-Dimensional-Model-based Electromagnetic Imaging

Cited by 21 publications

References 143 publications

Information metamaterials – from effective media to real-time information processing systems

Information metamaterials – from effective media to real-time information processing systems

Tunable, reconfigurable, and programmable metamaterials

Microwave Metamaterials

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