In this paper, we propose the design of a novel encoded metasurface for terahertz wavefront regulation. By employing an optimization algorithm to determine the optimal arrangement of elements, the proposed approach achieves significant broadband radar cross-section (RCS) reduction and high-quality holographic image reconstruction. This paper provides a practical and efficient means for THz wavefront control while highlighting the potential of coded metasurface technology in electromagnetic wave regulation. In applications such as radar stealth and wireless communication, reducing RCS and achieving high-resolution imaging are of critical importance. Consequently, this research holds significant scientific and practical value in advancing related technologies. In addition, by comparing with existing literature, this paper demonstrates the advantages of the designed coded metasurface in terms of design simplicity, broadband performance, RCS reduction, and holographic image reconstruction. These findings not only serve as a valuable reference for the academic community but also offer practical solutions for industrial applications, emphasizing their dual scientific and technological importance.

The research methodology involves the design and optimization of a coded metasurface for terahertz wavefront control using intelligent algorithms. A 2-bit coded metasurface for the terahertz band is proposed, leveraging the geometric phase principle and diffuse reflection theory to design a 2-bit coded superunit. The optimal arrangement of these elements is determined through an optimization algorithm to achieve broadband RCS reduction. For holographic imaging, based on the PB geometric phase principle, interference theory, and diffraction theory, four basic 2-bit coding elements are used to create the optimal phase layout through an optimization algorithm. This approach achieves a reduction of the RCS by more than 10 dB, up to 30.5 dB, across the 0.8?1.8 THz range, maintaining stable performance across incident angles from 0° to 40°, and enables high-quality holographic image reconstruction. To achieve these objectives, the genetic algorithm (GA) is employed to optimize the array layout, mimicking the natural selection to reduce RCS. For phase layout optimization, the Gerchberg-Saxton (GS) algorithm is used, combining iterative Fourier transforms and error calculation to restore high-quality holograms. MATLAB calculations and CST simulation tools are employed to ensure consistency and accuracy between theoretical and simulated results. This combination of methods demonstrates an efficient terahertz wavefront modulation technique, complementing existing solutions for radar stealth and holographic imaging technologies.

In this paper, we propose a novel coded metasurface for the terahertz band, achieving significant innovations. First, a double-cup-shaped coded metasurface element is introduced, characterized by simplicity, efficiency, and flexibility (Figs. 1 and 2). The phase and amplitude-frequency characteristics under different rotation angles are analyzed (Fig. 3). Four 2-bit coded superunits are designed (Fig. 4), and their optimal arrangement is determined through an optimization algorithm, resulting in notable broadband RCS reduction (Fig. 6). In the 0.8?1.8 THz range, RCS is reduced by more than 10 dB, with a maximum reduction of 30.5 dB (Figs. 7 and 8), and stable performance is maintained across incident angles from 0° to 40° (Figs. 9 and 10). Moreover, the GS algorithm optimizes phase layouts, enabling high-quality holographic imaging with accurate reconstruction (Figs. 12 and 13). These results highlight the effectiveness of coded metasurfaces for terahertz wavefront modulation. Using intelligent optimization algorithms, including GA and GS, we identify the most effective arrangements for RCS reduction and holographic imaging, achieving enhanced performance and efficiency. Preliminary MATLAB calculations, followed by CST simulations, confirm the consistency and accuracy of the results. This paper not only introduces a novel coded metasurface in theory but also demonstrates its practical potential in the terahertz band through simulation, revealing broad application prospects.

The coded metasurface designed in this paper achieves effective wavefront control in the terahertz band, offering significant application potential. By designing metasurface units capable of producing a phase difference of nearly 180° across a wide frequency band and maintaining an amplitude of 0.8 or higher, the metasurface demonstrates robust performance. Using phase gradient-based superunits, the array layout is optimized through intelligent algorithms, confirming effectiveness under varying polarizations and incidence angles. This leads to successful RCS reduction, with a maximum reduction of 30.5 dB across 0.8?1.8 THz and stable performance within incident angles of 0° to 40°. In addition, GS-based phase layout optimization achieves high-quality holographic imaging. Overall, this paper enhances the simplicity and broadband performance of existing technologies while offering new solutions for radar stealth and holographic imaging, demonstrating the significance of coded metasurfaces in electromagnetic wave regulation.