# Deep‐Subwavelength Slot‐Enhanced Broadband Dynamic Camouflage Metasurface Across the S, C, X, and Ku Bands

## TL;DR

A new metasurface design enables dynamic camouflage across multiple microwave bands by using tiny slots and vertical displacement.

## Contribution

The design introduces deep-subwavelength slots and vertical displacement to achieve broadband dynamic modulation in microwave camouflage.

## Key findings

- The metasurface modulates reflectivity from below −10 dB to near 0 dB across 2.7–19.1 GHz with 150.4% relative bandwidth.
- Deep-subwavelength slots (25 μm width) enable broadband dynamic modulation while maintaining polarization and angle insensitivity.
- The design is effective in the S, C, X, and Ku bands for countering advanced microwave imaging.

## Abstract

The rapid progress of microwave imaging technology has made conventional camouflage materials with fixed absorption performance ineffective. As the imaging band expands, camouflage materials capable of broadband operation, especially in the S and the C band, dynamic modulation are required to hide targets in complex environments. Here, we propose a dynamically modulated camouflage metasurface employing deep‐subwavelength slots to enhance multiband modulation capability. By varying the vertical displacement of the structure, reflectivity can be modulated from below −10 dB to near 0 dB over 2.7–19.1 GHz (150.4% relative bandwidth), while maintaining insensitivity to the incidence angle and polarization. An equivalent interface‐impedance model is established to reveal the mechanism of slot‐enhanced low‐frequency resonance. The laser processing parameters are optimized to reduce the slot width to 25 μm (λ
max/4440), enabling broadband dynamic modulation, as experimentally verified. Benefiting from its broadband dynamic modulation performance extending to the S and the C band, the proposed camouflage metasurface demonstrates potential for countering emerging microwave imaging technologies.

A deep‐subwavelength slot‐enhanced camouflage metasurface enabled by vertical displacement is demonstrated for broadband dynamic electromagnetic modulation. By introducing deep‐subwavelength slots, the operating bandwidth is significantly extended toward lower frequencies, while vertical uniaxial displacement allows continuous reflectivity modulation from −10 dB to near 0 dB across the S, C, X, and Ku bands.