Exploring the EM-wave diffusion capabilities of axicon coding metasurfaces for stealth applications.

Area of Science:

• Physics and Engineering
• Electromagnetics
• Metamaterials

Background:

• Coding metasurfaces are crucial for stealth applications, enabling diffusion scattering of electromagnetic (EM) waves.
• Existing design methods often lack systematic formulas and struggle to balance uniform diffusion with low reflected power without extensive optimization.
• The application of 2D axicon metasurfaces for diffusion and radar-cross-section reduction (RCSR) in stealth has not been previously explored.

Purpose of the Study:

• To present a novel single-layer coding metasurface design utilizing an axicon phase mask.
• To demonstrate efficient diffusion of EM waves and achieve significant RCSR for metallic objects.
• To offer a robust, computationally efficient design approach for stealth applications.

Main Methods:

• Design of a single-layer coding metasurface incorporating an axicon phase mask.
• Theoretical calculations to model EM wave diffusion and scattering.
• Numerical simulations and experimental validation to confirm performance.
• Analysis of RCSR and diffusive scattering under various incidence angles and polarizations.

Main Results:

• The proposed axicon coding metasurface achieves greater than 10 dB RCSR for normal incidence.
• The 10 dB RCSR bandwidth spans 15 to 35 GHz (80% fractional bandwidth) under normal incidence.
• Diffusive scattering and RCSR are maintained up to 60° off-normal incidence for all polarizations.
• The design demonstrates uniform diffusive scattering patterns and remarkable RCSR.

Conclusions:

• The presented axicon coding metasurface offers a fast, robust, and effective solution for EM wave diffusion and RCSR.
• This approach significantly enhances stealth capabilities for metallic objects.
• The design's wide bandwidth and angular stability make it highly attractive for practical stealth applications.