Experimental Time-Modulated Reflector Array

Wang, Y.; Tennant, A.

doi:10.1109/tap.2014.2362129

Cited by 28 publications

(7 citation statements)

References 16 publications

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“…As a first illustrative example, we address the design of a space-time-coding matrix for harmonic beam steering in one plane. Traditional time-switched arrays considered in previous studies 39 , 40 can realize harmonic beam steering by using time-gradient sequences, as illustrated in Fig. 2a, b .…”

Section: Resultsmentioning

confidence: 99%

Space-time-coding digital metasurfaces

et al. 2018

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The recently proposed digital coding metasurfaces make it possible to control electromagnetic (EM) waves in real time, and allow the implementation of many different functionalities in a programmable way. However, current configurations are only space-encoded, and do not exploit the temporal dimension. Here, we propose a general theory of space-time modulated digital coding metasurfaces to obtain simultaneous manipulations of EM waves in both space and frequency domains, i.e., to control the propagation direction and harmonic power distribution simultaneously. As proof-of-principle application examples, we consider harmonic beam steering, beam shaping, and scattering-signature control. For validation, we realize a prototype controlled by a field-programmable gate array, which implements the harmonic beam steering via an optimized space-time coding sequence. Numerical and experimental results, in good agreement, demonstrate good performance of the proposed approach, with potential applications to diverse fields such as wireless communications, cognitive radars, adaptive beamforming, holographic imaging.

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Section: Resultsmentioning

confidence: 99%

Space-time-coding digital metasurfaces

et al. 2018

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“…Then, such information metamaterials are referred as the time-space-coding information metamaterials, or time-modulated information metamaterials. In principle, the time-space-coding information metamaterial shares the same idea as that explored by the time-modulated or four-dimensional (4D) antenna array [85][86][87][88][89][90][91], originally proposed by Shanks and Bickmore in 1959 [85], where each antenna element is periodically or non-periodically switched "On" or "Off" in the time domain. The 4D antenna array lends itself to be more flexible in the beam scanning or forming, owing to the parameter-time can be electronically controlled, thus making it easier and more accurate to implement in reality.…”

Section: Time-space-coding Information Metamaterialsmentioning

confidence: 99%

“…Several time-modulated information metasurfaces have been investigated [87,[91][92][93][94][95][96]. Here, we discuss the time-space-coding information metasurface developed by Zhang et al [96].…”

Section: Time-space-coding Information Metamaterialsmentioning

confidence: 99%

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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“…Wang et al introduced the concept of time-modulated reflector array (TMRA) in [51], which was analyzed more deeply in [52]. A TMRA makes use of the topology of a conventional reflector array, i.e., consists of a matrix of scattering elements which are illuminated by a feed horn but, instead of phase shifters, it uses discrete time switching to achieve beam steering or beamforming functions.…”

Section: State Of the Artmentioning

confidence: 99%

Time Modulated Arrays: From their Origin to Their Utilization in Wireless Communication Systems

Maneiro-Catoira

Bregáins

García-Naya

et al. 2017

Sensors

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Time-modulated arrays (TMAs) are electromagnetic systems whose radiated power pattern is controlled by the application of variable-width periodical pulses to the individual elements. The nonlinear nature of the array operation causes the appearance of radiation patterns at the harmonic frequencies of such periodic pulses. The technique can be used for improving the side-lobe level (SLL) topology of the radiation pattern at the central frequency and/or to profitably exploit the harmonic patterns in order to supply smart antenna capabilities. Among the latter features, the TMA harmonic beamforming takes on special importance due to its attractive trade-off performance-hardware complexity. From this perspective, TMAs are sensors capable of transforming the spatial diversity of a communication channel into frequency diversity, thus improving the performance of a wireless communication. In addition to a walk through the origins of the concept, and a brief analysis of the mathematical fundamentals, this paper organizes the prolific state of the art of TMAs in two major thematic blocks: (1) TMA design from an antenna perspective; and (2) TMA design from a signal processing perspective.

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Experimental Time-Modulated Reflector Array

Cited by 28 publications

References 16 publications

Space-time-coding digital metasurfaces

Space-time-coding digital metasurfaces

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

Time Modulated Arrays: From their Origin to Their Utilization in Wireless Communication Systems

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