Broadband time-domain terahertz radar: Cross section measurement and imaging

Liang, Dachuan; Wei, Minggui; Gu, Jianqiang; Tian, Zhen; Ouyang, Chunmei; Han, Jiaguang; Zhang, Weili

doi:10.1109/irmmw-thz.2015.7327737

Cited by 5 publications

(4 citation statements)

References 4 publications

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“…The RCS characteristics of the sample are measured through a broad-band time domain THz RCS system32333435. The full width of the beam is 92 mm, the distance between the incident parallel wave and the target object is 1670 mm, and the distance between the scattered THz wave and the detector is 1410 mm.…”

Section: Resultsmentioning

confidence: 99%

Broadband and wide-angle RCS reduction using a 2-bit coding ultrathin metasurface at terahertz frequencies

Liu

Wei

Yan

et al. 2016

Sci Rep

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A novel broadband and wide-angle 2-bit coding metasurface for radar cross section (RCS) reduction is proposed and characterized at terahertz (THz) frequencies. The ultrathin metasurface is composed of four digital elements based on a metallic double cross line structure. The reflection phase difference of neighboring elements is approximately 90° over a broadband THz frequency. The mechanism of RCS reduction is achieved by optimizing the coding element sequences, which redirects the electromagnetic energies to all directions in broad frequencies. An RCS reduction of less than −10 dB bandwidth from 0.7 THz to 1.3 THz is achieved in the experimental and numerical simulations. The simulation results also show that broadband RCS reduction can be achieved at an incident angle below 60° for TE and TM polarizations under flat and curve coding metasurfaces. These results open a new approach to flexibly control THz waves and may offer widespread applications for novel THz devices.

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Section: Resultsmentioning

confidence: 99%

Broadband and wide-angle RCS reduction using a 2-bit coding ultrathin metasurface at terahertz frequencies

Liu

Wei

Yan

et al. 2016

Sci Rep

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“…Therefore, the FFT-based methods have to reconstruct several subimages block by block and then perform image stitching to form a large image. There are also many imaging algorithms based on time-domain correlation [18], [19] which process the received data directly in spatial domain and remove the intrinsic limitations of the FFTbased methods. However, the huge computational cost and data storage limit their practical applications.…”

Section: Introductionmentioning

confidence: 99%

“…x + x, y + y,r(∆x, 0, z ; x, y))• exp(j 4π λ cr (∆x, 0, z ; x, y))dydx+ ∆x+xm+1 xm+1yn+1 yn e r (x + x, y + y,r(∆x, 0, z ; x, y))• exp(j 4π λ cr (∆x, 0, z ; x, y))dydx(19) wherer(x +∆x, y , z ; x +x, y +y) =r(∆x, 0, z ; x, y), and e r (x, y,r(x + ∆x, y , z ; x, y)) ≈ e r (x, y,r(x , y , z ; x, y)) is valid due to the short interval (x m , x m+1 ] and (y n , y n+1 ].Compared with the original PCD imaging, an extra independent spatial correlation represented by the integral over the interval (y n , y n+1 ] in y-direction as shown in (19) is necessary before the recursive imaging in x-direction. To further reduce the computational cost, the integral over the area enclosed byx interval (x m , ∆x + x m ] and y interval (y n , y n+1 ] in (19) defined as S m,n (x + ∆x, y , z ) = ∆x+xm xm yn+1 yn e r (x + x, y + y,r(∆x, 0, z ; x, y)) • exp(j 4π λ cr (∆x, 0, z ; x, y))dydx (20) can be also calculated recursively along y-direction.…”

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confidence: 99%

3-D Terahertz Imaging Based on Piecewise Constant Doppler Algorithm and Step- Frequency Continuous-Wave Signaling

Nan

Huang

Gao

et al. 2021

IEEE Trans. Geosci. Remote Sensing

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A novel 3-D time-domain Teraherz (THz) imaging system based on piecewise constant Doppler (PCD) algorithm and step-frequency continuous-wave (SFCW) signalling is proposed in this paper. Firstly, the SFCW THz imaging system configuration and the Gaussian beam propagation model are introduced. Then, the conventional time-domain correlation imaging algorithm is reviewed and the close-form expression of its point spread function (PSF) is derived to quantify the range and lateral resolutions. To reduce the computational complexity, a 2-D recursive imaging process based on the plane approximation of the range surface is proposed, by which the original PCD algorithm is extended for 3-D imaging with 2-D aperture synthesis. The 3-D PCD imaging principle, implementation and complexity analysis are discussed afterwards. Finally, simulation and experimental results are provided to validate the theoretical analysis of the 3-D timedomain THz imaging and demonstrate the high quality of the proposed imaging algorithm at low computational cost.

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“…The unique position between electronics and photonics makes THz wave possess a series of unique properties [2], [3], such as transient, broadband, coherence, low energy and strong penetration. Thanks to these particularities, THz wave shows great potential applications [4]- [6] in communication technology, electronic weapon countermeasure, radar monitoring, medical imaging, biochemical inspection and…”

Section: Introductionmentioning

confidence: 99%

Tunable Linear-to-Circular Polarization Converter Using the Graphene Transmissive Metasurface

et al. 2019

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In this article, a tunable linear-to-circular polarization converter (LTCPC) in terahertz (THz) regime using the graphene transmissive metasurface is proposed, which is composed of two resonant layers containing the metal and graphene resonators separated by a dielectric spacer. The linearly-polarized wave with normal incidence can be transformed to the circularly-polarized wave. The operating band can be dynamically regulated in THz band by electrically controlling the Fermi energy (E f) of the graphene sheets rather than reforming the structures. The optimized result of axial ratio (AR) band which is less than 3 dB is located at 2.64-3.29 THz (the relative bandwidth is 21.92%) in the case of E f = 0.1 eV. The physical characteristics of graphene are explored and the relevant operational results of the presented LTCPC are elucidated in this article. Compared with the conventional LTCPC, our design provides a more effective implementation method for wide applications, and it offers a further step in graphene controllable devices.

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Broadband time-domain terahertz radar: Cross section measurement and imaging

Cited by 5 publications

References 4 publications

Broadband and wide-angle RCS reduction using a 2-bit coding ultrathin metasurface at terahertz frequencies

Broadband and wide-angle RCS reduction using a 2-bit coding ultrathin metasurface at terahertz frequencies

3-D Terahertz Imaging Based on Piecewise Constant Doppler Algorithm and Step- Frequency Continuous-Wave Signaling

Tunable Linear-to-Circular Polarization Converter Using the Graphene Transmissive Metasurface

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