With the rapid improvement of equipment integration technology, multi‐spectrum detectors are integrated into compact volumes and widely used for object detection. Confront with this challenge, it is essential to propose a strategy to design a single‐layer metasurface with multi‐spectrum responses in microwave and infrared ranges. In this work, we proposed a method of designing meta‐atoms, which is capable of achieving functional electromagnetic response at microwave and infrared individually. As a demonstration, a metasurface with four different occupation ratios and coding permutation features is designed, fabricated, and tested. In the microwave band, the pixel meta‐atom is designed to realize highly efficient cross‐polarization conversion between 5.0 and 10.0 GHz, which shows the metasurface can behave as ultra‐low Radar Cross Section (RCS) reflectors in the working band; In the infrared band, different occupation ratio of meta‐atoms are designed to realize the infrared emissivity from 0.60 to 0.80 in 3–14 μm, which can be used to exhibit digital infrared camouflage pattern. This work promotes the ability to use single‐layer design to achieve digital infrared camouflage and microwave RCS reduction simultaneously. The one‐layer design is simple in geometry, simplified in process, low cost in economy, and large scale in fabrication, which can promote practical use in compatible microwave stealth and infrared camouflage.

With the rapid development of detection technology and artificial intelligence, the widespread use of multispectral detectors has increased challenges to stealth capabilities. This paper presents a bispectral camouflage metasurface with microwave diffuse emission and tunable infrared (IR) emissivity, achieving an integrated design for radar cross-section (RCS) reduction and tunable IR emissivity. The structure consists of layers from bottom to top: aerogel felt, indium-tin-oxide (ITO), air, polyethylene terephthalate (PET), and ITO. It reduces RCS through microwave diffuse reflection and adjusts IR emissivity by controlling the ITO fill ratio. Both simulations and experiments demonstrate effective suppression of electromagnetic (EM) wave backscattering within 4.5–10.3 GHz, achieving radar invisibility. The tunable IR emissivity ranges from 0.2 to 0.7 with good thermal insulation. This design alleviates issues related to structural thickness and processing complexity and avoids increased thermal load from microwave absorption, offering better tunable IR emissivity for various thermal camouflage environments. This metasurface holds significant promise for multispectral stealth and IR camouflage applications.

To adapt to the complex environment where low infrared emissivity and high infrared emissivity coexist, a radar stealth-infrared camouflage compatibility metasurface requires meta-atoms with customized infrared emissivity. Generally, the infrared emissivity is determined by the occupation ratio. However, the high occupation ratio will interfere with the scattering reduction function due to the Lorentz resonance from the metal patch. To address the problem, a method for decoupling Lorentz resonance is proposed in this paper. By shifting the resonant frequency of the metal patch to a high frequency, the Lorentz resonance is suppressed in the frequency band of scattering reduction. To verify the method, a single functional layer metasurface with microwave scattering reduction and customized infrared emissivity is designed. The scattering reduction at 3.5–5.5 GHz is realized through the polarization conversion. Meanwhile, the infrared emissivity of the metasurface can be gradient-designed by changing the occupation ratios of the meta-atoms. Compared with the initial design, the improved metasurface expands the infrared emissivity range from 0.60–0.80 to 0.51–0.80, and the scattering reduction effect remains unchanged. The experimental results agree with the simulated results. The work enriches the infrared emissivity function, which can be applied to camouflage in complex spectrum backgrounds.

Multispectral compatible stealth of high-value targets has intrigued long-standing interest in response to the rapid development of multispectral detection technologies, and a series of ingenious metasurfaces profiting from the exotic electromagnetic (EM) property has provided exceptional platforms for realizing multispectral compatible stealth. Nevertheless, most existing multispectral compatible stealth metasurfaces still suffer from the drawback of immutable stealth performance, which tremendously hinders their practical application in various complex scenarios. Herein, an inspiring strategy of the programmable coding metasurface (PCM) with a thickness of approximately 0.1 λ ₀ is proposed to fulfill dynamic microwave manipulation, low infrared radiation, and high optical transparency. Owing to continuous amplitude dynamic modulation and 1-bit phase dynamic modulation implemented by adjusting the PIN diodes of well-designed meta-atoms, the proposed PCM is capable of independently and dynamically controlling the absorption intensity and scattering direction of EM waves in broad bandwidth. Simultaneously, the average infrared emissivity of the PCM can be reduced to about 0.25 from 3 to 14 μm, attributed to the low infrared radiation of the surface indium-tin-oxide (ITO) structures, and the optical transparency can reach 65.9% at 565 nm due to the design of the copper mesh structure and the selection of the transparent dielectric substrate. Multitudinous simulations and experiments of the proof-of-concept prototype are in accordance with theoretical predictions and corroborate the effectiveness of our methodology. This remarkable paradigm of the PCM shows unprecedented intelligence and integration in multispectral compatible stealth and may also find potential applications in communication, imaging, and other intelligent metadevices.

The high degree of freedom of multimechanism metasurfaces has greatly facilitated multifunction or even multiphysics design for practical applications. In this work, to achieve camouflages simultaneously in microwave, infrared, and optical regimes, we propose a multimechanism-empowered metasurface composed of four elemental indium-tin-oxide-based meta-atoms. Each meta-atom can modulate microwaves both in phase and magnitude through polarization conversion and resonance absorption, which can realize radar stealth at 8–14 GHz. The reflective amplitude is less than −10 dB. When the incident angle increases to 60°, the reflective amplitude is still less than −3 dB. The far-field scattering patterns of microwaves are modulated by destructive interferences of reflected waves, which results in diffusion-like scattering due to randomly distributed reflection phases on the metasurface. The superposition of microwave absorption and diffuse reflection enables broadband microwave scattering reduction of the metasurface. Meanwhile, the emissivity of four types of meta-atoms covers from 0.3–0.8 at 3–14 μm due to delicately designed occupation ratios. The infrared radiation of the metasurface exhibits the characteristics of digital camouflage in infrared imaging. To demonstrate this method, prototypes were fabricated and measured. The measured results are consistent with the simulated ones. The angular stability in the microwave range within 0°–60° was also demonstrated. This work presents an approach to achieving multispectrum functions with integrated multimechanisms in a single functional metasurface layer and offers a new methodology for custom-designing infrared performance. Moreover, the simplicity of the structure offers significant cost control and large-scale fabrication advantages.

In recent years, reconfigurable metasurfaces (RMs), as real-time controllable 2-D metamaterials, have become an emerging platform for manipulating spatial electromagnetic (EM) waves by loading dynamic components. To date, many RMs have been reported, most of which are without special considerations on optical transmittance or only support limited functions of absorption and reflection. In this work, we propose an optically transparent RM (OTRM) window simultaneously with customized transparency for sunlight-proof and switchable transmission of microwaves for EM pollution prevention. The metasurface window is based on an optically transparent substrate with a metallic mesh, which can reduce the proportion of opaque space required to customize the optical transmittance. The dual-layer rheostatic diodes implement dynamic control of transmission, absorption, and reflection of EM waves, including continuous modulation and complete switch-on/off in the microwave band (5.2–6.4 GHz). The working mechanism of the metasurface in the microwave band was theoretically explained using the Drude model and the Lorentz model. A proof-of-concept prototype was designed, fabricated, and measured, further demonstrating sunproof optical transparency and switchable control of EM waves. This work may find applications in future 5G or 6G intelligent wireless communications for diverse EM modulations.