Background
Metasurfaces—2D arrays of subwavelength artificial units—have gained attention for their electromagnetic wave manipulation capabilities. Programmable metasurfaces, which embed tunable elements (e.g., PIN diodes), enable real-time digital control for beamforming, information modulation, and smart surfaces (key to 6G). However, existing work focuses on radiation performance (e.g., beam scanning, gain), with limited in-band stealth via phase cancellation. A critical gap persists: stealth is confined to operational bands, leaving systems vulnerable in other radar bands (e.g., S-/C-band).
Research Progress
This study addresses the challenge of integrating in-band communication/radiation with multi-band stealth in a single programmable metasurface. The "self-stealth" mechanism uses an intrinsic co-aperture design to achieve RCS reduction across in-band and multiple out-of-band frequencies. This eliminates added height, RF loss, and external structures, enabling next-generation integrated RF fronts for smart communication, sensing, and full-spectrum stealth. PIN diodes dynamically control 1-bit in-band x-polarized phase for ±45° beam scanning, while y-polarized structures suppress scattering—synchronizing communication and stealth. Cross-dumbbell and branched structures on the metasurface's top/middle layers cover four out-of-band frequencies. Checkerboard patterning cancels scattering without absorbers/radomes. Five resonators independently tune low- (fl₂=3.6 GHz, fl₁=4.16 GHz), center- (f₀=5.2 GHz), and high-frequencies (fh₂=6.55 GHz, fh₁=7.43 GHz), achieving 180°±37° phase differences across 70% bandwidth. Total thickness is 0.065λ (λ at 5.2 GHz), 87% thinner than conventional designs (0.51λ)—ideal for conformal aircraft/drone integration. A 12×12 prototype was fabricated and tested, with results matching simulations. Communication: 2D ±45° beam scanning at 5.2 GHz, peak gain of 17.23 dBi, aperture efficiency of 18%. Significant RCS reduction in all five bands: In-band: >−6 dB reduction for x-pol (4.9–5.3 GHz) and y-pol (5.0–5.38 GHz). Out-of-band: >−10 dB reduction across four stopbands.
Future Prospects
This research marks a pivotal step toward multifunctional integration in programmable metasurfaces. For the first time, dynamic beamforming communication and broadband self-stealth coexist on a single low-profile platform, resolving performance/power/integration trade-offs. Such "self-stealth" metasurfaces offer hardware solutions for 6G integrated sensing-communication, stealth-platform communication systems, intelligent electromagnetic camouflage. Like an "intelligent skin" for equipment, it enables sensitive signal transmission/reception while intelligently concealing itself—advancing electromagnetic materials and system design.
Sources: https://spj.science.org/doi/10.34133/research.1017
Research
News article
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A Low-Profile Self-Stealth Programmable Metasurface with In-Band and Out-of-Band RCS Reduction
4-Dec-2025