Research on monostatic and bistatic RCS of cloaking based on coordinate transformation

Ji, Jinzu; Jiang, Jiaxin; Chen, Guoxu; Liu, Feiliang; Ma, Yunpeng

doi:10.1016/j.ijleo.2018.03.063

Cited by 7 publications

(4 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, it has been established that -10-dB RCS reduction can be maintained over a frequency band if the phase difference between the two AMC cells remains within the 143 • -217 • range (i.e., 180 • ± 37 • ) [24]. More recently, the concepts of coding metasurfaces [25], diffusion metasurfaces [26], [27], programmable metasurfaces [30], Huygens' metasurfaces [31], and cloaking structures [32] have been proposed, which offer a control over the wavefront in a more sophisticated manner. The primary advantage of coding and diffusion metasurfaces over the checkerboard type surfaces is that it scatters the incident EM waves into all directions.…”

Section: Introductionmentioning

confidence: 99%

Machine-Learning-Powered EM-Based Framework for Efficient and Reliable Design of Low Scattering Metasurfaces

Koziel

Abdullah

2021

IEEE Trans. Microwave Theory Techn.

View full text Add to dashboard Cite

Popularity of metasurfaces has been continuouslygrowing due to their attractive properties including the ability to effectively manipulate electromagnetic (EM) waves. Metasurfaces comprise optimized geometries of unit cells arranged as a periodic lattice to obtain a desired EM response. One of their emerging application areas is the stealth technology, in particular, realization of radar cross section (RCS) reduction. Despite potential benefits, a practical obstacle hindering widespread metasurface utilization is the lack of systematic design procedures. Conventional approaches are largely intuitioninspired and demand heavy designer's interaction while exploring the parameter space and pursuing optimum unit cell geometries. Not surprisingly, these are unable to identify truly optimum solutions. In this article, we introduce a novel machine-learningbased framework for automated and computationally efficient design of metasurfaces realizing broadband RCS reduction. Our methodology is a three-stage procedure that involves global surrogate-assisted optimization of the unit cells, followed by their local refinement. The last stage is direct EM-driven maximization of the RCS reduction bandwidth, facilitated by appropriate formulation of the objective function involving regularization terms. The appealing feature of the proposed framework is that it optimizes the RCS reduction bandwidth directly at the level of the entire metasurface as opposed to merely optimizing unit cell geometries. Computational feasibility of the optimization process, especially its last stage, is ensured by high-quality initial designs rendered during the first two stages. To corroborate the utility of our procedure, it has been applied to several metasurface designs reported in the literature, leading to the RCS reduction bandwidth improvement by 15%-25% when compared with the original designs. Furthermore, it was used to design a novel metasurface featuring over 100% of relative bandwidth. Although the procedure has been used in the context of RCS design, it can be generalized to handle metasurface development for other application areas.

show abstract

Section: Introductionmentioning

confidence: 99%

Machine-Learning-Powered EM-Based Framework for Efficient and Reliable Design of Low Scattering Metasurfaces

Koziel

Abdullah

2021

IEEE Trans. Microwave Theory Techn.

View full text Add to dashboard Cite

show abstract

“…On the other hand, it has been shown that -10 dB RCS reduction can be maintained over a frequency band if the phase difference between the two unit cells remains within 180° ± 37° range [26]. In a related vein, the concepts of coding metasurfaces [27], [28], diffusion metasurfaces [29], [30], programmable metasurfaces [31], Huygens' metasurfaces [32], as well as cloaking structures [33], have been proposed, which offer a control over the wavefront in a more sophisticated manner. The primary advantage of coding and diffusion metasurfaces over the checkerboard type surfaces is that it scatters the incident EM waves into all directions.…”

Section: Introductionmentioning

confidence: 99%

Surrogate-Assisted Design of Checkerboard Metasurface for Broadband Radar Cross-Section Reduction

Abdullah

Koziel

2021

IEEE Access

View full text Add to dashboard Cite

Metasurfaces have been extensively exploited in stealth applications to reduce radar cross section (RCS). They rely on the manipulation of backward scattering of electromagnetic (EM) waves into various oblique angles. However, arbitrary control of the scattering properties poses a significant challenge as a design task. Yet it is a principal requirement for making RCS reduction possible. This article introduces a surrogate-based approach for rapid design optimization of checkerboard metasurfaces. Our methodology involves fast metamodels, and a combination of surrogate-assisted global optimization with local, gradientbased tuning. It permits an efficient control of the EM wave reflection characteristics, and ensures arriving at that the globally optimum solution within the assumed parameter space. The design procedure is fully automated. The framework is employed to develop a novel broadband checkerboard metasurface, where the RCS reduction is fundamentally based on the backward scattering manipulation carefully controlled by simultaneous adjustment of the unit cell dimensions. The properties of the structure are demonstrated using simulated monostatic and bistatic RCSs. The proposed metasurface exhibits 6 dB RCS reduction within the frequency range from 16 to 37 GHz. The numerical results are validated using physical measurements of the fabricated prototype. Experimental data indicates that the relative RCS reduction bandwidth is 83 percent, which makes the proposed structure outperforming the designs reported in the literature. INDEX TERMS Metasurfaces, surrogate modeling, scattering manipulation, checkerboard configuration, radar cross-section (RCS), broadband.

show abstract

“…In addition to that, coding metasurfaces are also being exploited as an absorptive surface to realize essential RCS reduction [20]. In a related vein, the concept of programmable metasurfaces [21], Huygens' metasurfaces [22], and cloaking structures [23], have also been proposed to accomplish RCS reduction.…”

Section: Introductionmentioning

confidence: 99%

Design of High-Performance Scattering Metasurfaces Through Optimization-Based Explicit RCS Reduction

2021

View full text Add to dashboard Cite

The recent advances in the development of coding metasurfaces created new opportunities in realization of radar cross section (RCS) reduction. Metasurfaces, composed of optimized geometries of meta-atoms arranged as periodic lattices, are devised to obtain desired electromagnetic (EM) scattering characteristics. Despite potential benefits, their rigorous design methodologies are still lacking, especially in the context of controlling the EM wavefront through parameter tuning of meta-atoms. One of the practical obstacles hindering efficient design of metasurfaces is implicit handling of RCS performance. To achieve essential RCS reduction, the design task is normally formulated in terms of phase reflection characteristics of the meta-atoms, whereas their reflection amplitudes-although contributing to the overall performance of the structure-is largely ignored. As a result, the conventional approaches are unable to determine truly optimum solutions. This article proposes a novel formulation of the metasurface design task with explicit handling of RCS reduction at the level of meta-atoms. Our methodology accounts for both the phase and reflection amplitudes of the unit cells. The design objective is defined to directly optimize the RCS reduction bandwidth at the specified level (e.g., 10 dB) w.r.t. the metallic surface. The benefits of the presented scheme are twofold: (i) it provides a reliable insight into the metasurface properties even though the design process is carried out at the level of meta-atoms, (ii) the obtained design requires minimum amount of tuning at the level of the entire metasurface. None of these is possible for phase-response-based approach fostered in the literature. For practical purposes, the design is conducted using a surrogate-assisted procedure involving kriging metamodels, which enables global optimization at a low computational cost. To corroborate the utility of our formulation, a high-performance metasurface incorporating crusader-crossshaped meta-atoms has been developed. The obtained results indicate that the system characteristics predicted at the design stage are well aligned with those of the EM-simulated structure (which is not the case for the traditional design approach). The metasurface features 10-dB RCS reduction in the frequency range of 16.5 GHz to 34.6 GHz, as validated both numerically and experimentally. INDEX TERMS Radar cross section (RCS), periodic structures, design task, optimization, scattering.

show abstract

Research on monostatic and bistatic RCS of cloaking based on coordinate transformation

Cited by 7 publications

References 12 publications

Machine-Learning-Powered EM-Based Framework for Efficient and Reliable Design of Low Scattering Metasurfaces

Machine-Learning-Powered EM-Based Framework for Efficient and Reliable Design of Low Scattering Metasurfaces

Surrogate-Assisted Design of Checkerboard Metasurface for Broadband Radar Cross-Section Reduction

Design of High-Performance Scattering Metasurfaces Through Optimization-Based Explicit RCS Reduction

Contact Info

Product

Resources

About