Time-Domain Digital-Coding Active Frequency Selective Surface Absorber/Reflector and Its Imaging Characteristics

Wang, Junjie; Feng, Dejun; Xu, Zhiming; Wu, Qing; Hu, Weidong

doi:10.1109/tap.2020.3037757

Cited by 44 publications

(20 citation statements)

References 34 publications

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“…( 10)-( 12), the DFM parameter ξm is used for controlling and tailoring the overall spectrum of the scattered field, defining the apparent distance and of false targets to be generated. For example, if we want to emulate a uniform time-modulated metasurface as in [30], [31], the parameter ξm is a constant in (10) allowing to generate a single false target and making hard to realize flexible false targets properties at different observation angles with only the number of harmonic h which is irrelevant to the element number m. On the contrary, if we want to realize a set of specific false targets at different observation angles, the DFM parameter can be configured along y-direction. In the following, we can make use of analytical or optimization numerical methods [36], [37] to design specific frequency spectrum of element and DFM parameters, aiming at obtaining the desired false targets at different observation angles.…”

Section: False Targets Jamming In Fmcw Radarsmentioning

confidence: 99%

“…5 (d) and Fig. 8, when DFM parameter ξm = [1 1 1 1 1 1 1 1] corresponding to a uniform time-modulated metasurface as in [30], [31], the amplitude of designed false targets decrease away from the specular reflection angle, and amplitude fluctuation of false targets is caused by the superposition with spatial phase delays at different observation angles [38].…”

Section: B Df-mts False Targets Jamming At Different Anglesmentioning

confidence: 99%

“…Theory and Experiment Xinyu Fang, Mengmeng Li, Senior Member, IEEE, Shiyuan Li, Davide Ramaccia, Senior Member, IEEE, Alessandro Toscano, Senior Member, IEEE, Filiberto Bilotti, Fellow, IEEE, and Dazhi Ding, Senior Member, IEEE F making the target appearing as if it were accelerating or decelerating for the receiving radar system and hiding its real position [27]. On the contrary, in [30] the temporal modulation is applied to the surface resistance of the metasurface switching periodically the surface properties from the reflecting to the absorbing state. Such an approach can realize several false targets, but the real target can not be canceled by the modulation of the reflection amplitude over time.…”

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confidence: 99%

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Diverse Frequency Time-Modulation for Passive False Target Spoofing: Design and Experiment

Li¹,

Ramaccia²,

Toscano³

et al. 2023

Preprint

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<p>This paper presents a false target jamming method for linear frequency modulated (LFM) radar based on diverse frequency time-modulated metasurface (DF-MTS). The DF-MTS is composed by a set of elements, each of which is independently time-modulated to realize specific false targets in the high-resolution range profile (HRRP) of the radar system. Thanks to the control of the modulation scheme in each element of the metasurface and the combined response of the overall surface, we demonstrate the capability to realize several false target patterns consisting of single and multiple targets symmetrically, or non-symmetrically, distributed around the actual target. A general expression of one-dimension HRRP of DF-MTS at different observation angles is given to show the relation between the generated false targets and frequency components. Due to the flexible capacity of scattered field manipulation, DF-MTS has enhanced performance on control of false target jamming at different observation angles. Both simulated and measured results demonstrate the validity of false targets manipulation, demonstrating its effectiveness as electromagnetic countermeasure for achieving radar camouflaging and deception. </p>

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Section: False Targets Jamming In Fmcw Radarsmentioning

confidence: 99%

Section: B Df-mts False Targets Jamming At Different Anglesmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Diverse Frequency Time-Modulation for Passive False Target Spoofing: Design and Experiment

Li¹,

Ramaccia²,

Toscano³

et al. 2023

Preprint

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show abstract

“…Wang et al designed a time-domain digital-coding AFSS absorber/reflector to modulate electromagnetic waves. The imaging features were analysed in detail, and the distance transformation phenomenon was described [26]. The above research studies are mainly based on periodic modulation, and there is little attention to other modulation waveforms.…”

Section: Introductionmentioning

confidence: 99%

A method for transforming 2D imaging features with the AFSS‐loaded rotating Luneberg lens reflector

Feng

Wang

et al. 2022

IET Microwaves Antenna & Prop

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The micro‐motion target can perform micro‐Doppler modulation on the electromagnetic wave due to motion components in different directions, leading to the defocus effect of the target imaging feature along the azimuth direction. This phenomenon has been widely concerned and investigated in the field of target recognition and anti‐recognition. However, the micro‐motion target fails to transform image features along the distance direction according to its slow mechanical modulation speed. In comparison, electromagnetic metasurfaces can flexibly control the characteristics of electromagnetic waves with faster modulation speed through electronic control. It can realize the image feature transformation along the range direction. Inspired by this idea, a joint modulation method of rotational micro‐motion and electronic control through an active frequency selective surface (AFSS)‐loaded rotating Luneberg lens reflector is proposed. The signal models of micro‐motion modulation and non‐periodic AFSS modulation are established separately. On this basis, the imaging properties of the joint modulation are further analysed and the two‐dimensional (2D) defocusing phenomenon of the image is discovered. Moreover, the simulation of the measured synthetic aperture radar (SAR) data with different modulation methods is conducted to demonstrate the effectiveness of the proposed method.

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“…Microwave-based absorber such an example that absorb electromagnetic radiation even the changing of polarization and direction but still appear broader bandwidth. Absorbers are used in a variety of applications such as energy harvesting efficiency [1], radar imaging and reducing radar cross-section [2], thermal emission [3], sensing or enhancing detection sensitivity [4], solar cells [5], and photodetection [6]. Metamaterial-based absorbers provide unusual characteristics due to their artificial sub-lambda structure.…”

Section: Introductionmentioning

confidence: 99%

A Broadband Polarized Metamaterial Absorber Driven by Strong Insensitivity and Proximity Effects

2021

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Artificial electromagnetic metamaterial produces exotic resonance, unusual characteristics not found in nature, but engineers can inherit the characteristics by controlling and manipulating their architecture. The design and realization of dual-band, polarization, and incident angle insensitive metamaterial absorber (MA) is proposed. By manipulating shape and structure, periodic pattern, and dielectric layer thickness a significant way to realize high absorption has been investigated. In order to achieve high absorption a new shape of an octagonal ring (OR), cross-wires (CWs), and cut-off circle (CC) artificial structure have been carefully chosen. The special characteristics of this structure produce a dual resonance and its bandwidth increases compare to the classical absorber. The proposed artificial structure operation suits the Ku-band application, but possible to enhance in C-band. The numerical and experimental results show a dual-band 99.8% at 12.2 GHz and 99.9% at 15.5 GHz resonance is an excellent agreement in theory and numerical analysis. The effects of the constitutive property parameters: dielectric constant (ɛ), magnetic permeability (µ), and negative refractive index (n) are also investigated. The investigation of symmetric design structure shows the polarization-insensitivity and high absorption found even in changing the incident angle. Numerical and experimental results ensured the destructive interference of multiple penetrations which are responsible for the near-unity absorption. An excellent agreement in the absorptivity rates that touches near perfection which is prominent for solar cells, detection, and imaging applications.

show abstract

Time-Domain Digital-Coding Active Frequency Selective Surface Absorber/Reflector and Its Imaging Characteristics

Cited by 44 publications

References 34 publications

Diverse Frequency Time-Modulation for Passive False Target Spoofing: Design and Experiment

Diverse Frequency Time-Modulation for Passive False Target Spoofing: Design and Experiment

A method for transforming 2D imaging features with the AFSS‐loaded rotating Luneberg lens reflector

A Broadband Polarized Metamaterial Absorber Driven by Strong Insensitivity and Proximity Effects

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