Wave Absorption Research Articles

Terahertz characterization of organic crystals using paraffin as dilution matrix

Terahertz waves exhibit excellent performance in molecular information detection of substances. Since natural materials exhibit weak absorption of terahertz waves, it's conventional to involve mixing analyte with polymer diluents and pressing them into pellets, or enhance the light-material interaction through coupling systems of natural materials with metamaterials. However, both pressure-induced metastable crystal structure transformations and spatial overlap between the analyte and metasurfaces can impact the absorption of terahertz waves by organic crystals. This paper proposes a novel analytical approach using paraffin as a dilution matrix for qualitatively and quantitatively characterizing organic crystals with THz spectroscopy. The featureless refractive index spectra and negligible absorption demonstrated the feasibility of paraffin as a diluting analyte. The analytical process was further demonstrated with well-studied lactose by being diluted in molten paraffin at different mass-ratios and solidified as pellets under room temperature and ambient pressure. A continuous wave terahertz frequency domain spectroscopy system (THz-FDS) is used for spectral acquisition over 0.4–1.3 THz. The experimental results reveal a significant linear correlation between the absorption coefficient peak areas and molar concentration of lactose, with a correlation coefficient R2 of 0.9678. Our method provides an additional optional dilution matrix for terahertz spectroscopy characterization of organic crystals, enabling non-destructive, rapid, and direct measurement of metastable crystals. Furthermore, this study on paraffin as a binder material holds potential for enhancing spatial overlap between natural materials and metamaterials in the field of metasurface-enhanced sensing.

High temperature flexible 2D metasurface based on optimal design for thermal insulation and electromagnetic wave absorption skin

The development of radar stealth skin with long term stable service and flexible deformability is the premise and foundation of improving the battlefield survivability of deformable aircraft. Aiming at the bottleneck problem of mismatch between the flexible configuration and the electromagnetic configuration of the existing stealth composite materials, a new type of SiO2 fiber paper (SFP) with flame retardant, thermal insulation, low dielectric constant and super-hydrophobic was prepared by combining the papermaking process with surface modification. The effects of solid content and high temperature environment on the mechanical properties, thermal insulation properties, dielectric properties and hydrophobic properties of SFP materials were studied in detail. Based on this, the optimal design and construction method of radar stealth metasurface suitable for flexible deformation are proposed, and the high temperature resistant flexible stealth skin metasurface is obtained. The metasurface has been demonstrated to achieve an effective wave absorption of −8 dB in the 10.9–16.4 GHz range at 400 μm thickness, making it an ideal candidate for flame retardant, flexible, thermal insulation and radar stealth skin under extreme conditions. It provides theoretical basis and technical support for the innovative development of high-speed deformable stealth aircraft.

Zn-Zr substituted M-type Sr-hexaferrites for effective electromagnetic wave absorptions in the 26.5–40 GHz range

This study explores the electromagnetic (EM) wave absorption properties of Zn-Zr substituted M-type Sr-hexaferrites (SrFe12–2xZnxZrxO19, x = 0.3, 0.4, 0.5, 0.6) integrated into polymer composites (10 wt%, epoxy or rubber). The hexaferrite powders were synthesized using solid-state reaction processes with and without the molten-salt (M-S) method. Compared to non-M-S samples, those processed with M-S exhibited larger grain sizes and more defined grain edge shapes without clustering. High-frequency characteristics (ε', ε", μ', and μ") and EM wave absorption properties, specifically reflection loss (RL), were evaluated over the frequency range of 26.5 ≤ f ≤ 40 GHz. Regardless of the M-S method application, hexaferrite-epoxy composites (10 wt%) demonstrated excellent EM wave absorption properties with RLmin < −40 dB and a shifting absorption band corresponding to variations in x, reflecting changes in the ferromagnetic resonance frequency (fFMR). For the x = 0.4 sample, flexible rubber binder (10 wt%) sheets dispersed with hexaferrite powder were fabricated, showing superior broadband absorption characteristics compared to epoxy composites. In rubber sheet form, M-S processed samples exhibited enhanced μ', μ" spectra and improved absorption performance compared to non-M-S samples. The M-S processed hexaferrite-rubber sheet demonstrated broad EM wave performance with RL < −10 dB across the entire frequency range, achieving RLmin = −61 dB at 32 GHz. This study underscores the potential of Zn-Zr-substituted SrM-polymer composites for robust EM wave absorption performance in the Ka-band (26.5–40 GHz), crucial for applications in 5 G communication frequencies.

Regulating the phase composition and microstructure of Fe3Si/SiC nanofiber composites to enhance electromagnetic wave absorption

The rational introduction of multi-components to fabricate electromagnetic wave absorbing (EMA) materials with synergistic conductive/dielectric/magnetic losses promises lightweighting and excellent EMA performance, but it remains a challenge. In this work, multicomponent Fe3Si/SiC nanofibre composites with network structure were constructed by electrostatic spinning method and in-situ carbothermal reduction strategy. Design of microstructures and multicomponent modulation by controlling the carbothermal reduction temperature. As a result, the presence of a large number of non-homogeneous interfaces, three-dimensional (3D) conductive network structures and defect structures in Fe3Si/SiC nanofibre composites induces a combination of multiple loss mechanisms that significantly improve the EMA performance. When the filling amount of Fe3Si/SiC in the paraffin transmission matrix is 20 wt%, the maximum effective absorption bandwidth (EABmax) of the fabricated material reaches 5.84 GHz with a thin thickness of 2.02 mm. Moreover, the minimum reflection loss (RLmin) value at 10.96 GHz is as low as −67.57 dB. Meanwhile, the radar cross-section (RCS) simulation verifies that the F-4 peak RCS is reduced to −30.37 dB in the range of −60°<θ < 60°. It indicates that the Fe3Si/SiC nanofiber composites have a good radar-wave dissipation capability in practical applications. In summary, the comprehensive performance of lightweight multicomponent Fe3Si/SiC nanofiber composites can meet the new application requirements and is expected to become an emerging multifunctional wave-absorbing material suitable for harsh environments.

Fe3C/Fe implanted hierarchical porous carbon as efficient electromagnetic wave absorber

The rapid development of communication technology has led to severe microwave pollution, which presents a challenge for microwave-absorbing composites. Current research suggests achieving superior microwave absorption requires the use of multi-component operation and ingenious structural design. Consequently, the present study has prepared continuous porous carbon (CPC) materials doped with large amounts of Fe3C/Fe nanoparticles (Fe@CPC) using carbonization and acid etching. By balancing the advantages of the above strategies, it is possible to address issues such as poor impedance match, single loss capacity, easy oxidation of magnetic metals/alloys, and the limited absorption bandwidth of conventional absorbing materials at the same time. The material exhibits a minimum reflection loss of −23.2 dB with an efficient absorption range of 5.3 GHz at 1.9 mm at a filler content of just 10 wt% in the paraffin matrix. In this paper, the samples with a continuous porous structure were prepared by a simple method, and the properties were excellent due to the appropriate preparation method and the synergistic effect of the multi-component composite. The porous structure facilitates the presence of a considerable number of active sites, which enables the loading of a substantial quantity of metal ions. Furthermore, nanoparticles are capable of aggregating and dispersing on the surface. This paper presents a theoretical framework for understanding the synergistic effect of microwave radiation through interfacial polarization and micro-scale magnetic interaction. Nevertheless, there are still obstacles to overcome in terms of achieving precise control over the structural design and ensuring the compatible integration of metal components.

Defect design and vacancy engineering of NiCo2Se4 spinel composite for excellent electromagnetic wave absorption

Vacancy engineering presents an appealing method for modifying the electronic structure of spinel architectures. However, based on well-defined vacancy concentrations, how to design anionic vacancies to modulate electromagnetic parameters as well as electromagnetic wave absorption (EMA) properties is less studied. Here, NiCo2Se4 spinel structures were prepared using different selenization methods, and the Se vacancy defect concentration was controlled by changing the annealing temperature, thus regulating the EMA properties. Among them, the design of the hollow structure effectively enhanced the EMA performance. Moreover, the increase of Se vacancy concentration increases the conductivity loss while regulating the electronic structure, and also acts as an unsaturated site to induce the formation of dipoles to optimize the polarization loss. The effective absorption bandwidth (EAB) of NiCo2Se4-130 reaches 8.48 GHz at 2.4 mm at the highest Se vacancy concentration. This work establishes a direct relationship between vacancy concentration and the electromagnetic wave dissipation capability, offering valuable insights for the development of advanced EMA materials.

Transparent antenna with RCS tunability based on graphene and metasurface in S band

In this paper, we propose a graphene-based radar cross section (RCS) tunable antenna that utilizes metal mesh and graphene, both of which are optically transparent. The graphene sandwich structure is introduced to replace traditional components like diodes, micro-electro-mechanical systems (MEMS), and varactors, acting as an electromagnetic wave controller and significantly simplifying the device's complexity. By applying different voltages, the electrical properties of graphene are altered, enabling the regulation of reflection, transmission, and absorption of electromagnetic waves. This not only modifies the antenna's pattern but also achieves a substantial reduction in out-of-band RCS. The radiation and scattering mechanism of the antenna is carefully elaborated. The numerical and experimental results match well, which validates the effectiveness of the proposed method. The optical transmittance of the device is 27.9% at 550 nm, and the out-of-band RCS reduction is 10.01 dB at 3.83 GHz. The transparent, RCS tunable antenna proposed has significant potential applications in optical and microwave stealth technology.

A p-Multigrid Hybrid-Spectral Model for Nonlinear Water Waves

AbstractTo improve both scale and fidelity of numerical water wave simulations to study the evolution of wave fields within offshore engineering, it is of key practical interest to achieve high numerical efficiency. We propose a p-multigrid accelerated time-domain scheme for efficient and $${\mathcal {O}}(n \log n)$$ O ( n log n ) -scalable solution of a hybrid-spectral model for the simulation of highly nonlinear and highly dispersive water waves, the accurate calculation of wave kinematics and taking into account varying water depth. To achieve low numerical dispersive and dissipate errors, a high-order hybrid-spectral collocation scheme is implemented to solve the fully nonlinear potential flow (FNPF) equations, and utilizing a p-multigrid iterative solver scheme for solving the Laplace problem. Hereby, the numerical scheme combines the high accuracy of spectral methods, high efficiency of the fast Fourier transform (FFT) algorithm, and multigrid methods. Numerical analysis is performed to evaluate the performance and confirm the spectral accuracy of the scheme. Numerical experiments are considered for steady nonlinear wave propagation. A Fourier-continuation technique is used to extend the scheme from a periodic domain setup to perform benchmarks in a finite domain setup for numerical wave tanks utilizing conventional techniques for wave generation and absorption, and with results in excellent agreement with experimental measurements.

Advantageous Effects of Phase Transition-Modulated Electric Polarization of Hollow CuSx for Enhanced Electromagnetic Wave Absorption.

Scrutinizing the electromagnetic wave absorption mechanism of sulfides remains a challenge due to the variability of the modulation of the crystal structure of the sulfides. To take advantage of this variability, nanosheet-assembled Cu9S5/CN composites with sulfur vacancies were prepared in this study by self-assembly synthesis and subsequent high-temperature heat treatment. Systematic studies show the phase transition-dependent induced decrease in the conductivity, the defect site-induced difference in the charge density, the weakened vacancy formation of defect polarization loss, and the influence of valence state on electric dipole polarization loss and interfacial polarization loss, making the optimization of the dielectric constant a significant positive effect on the improvement of impedance matching. This work provides a reliable example and theoretical guidance for the crystal structure design for the preparation of a new generation of efficient sulfide-based wave-absorbing materials.

Confined magnetic nickel nanoparticles in carbon microspheres with high-performance electromagnetic wave absorption in Ku-band

Composition and structure regulation is the primary strategy in preparing high-performance electromagnetic (EM) wave absorption materials. Herein, magnetic-dielectric synergy Ni@C microspheres were fabricated to obtain the high-performance electromagnetic (EM) wave absorption performance. Firstly, the Ni-containing precursor microspheres were obtained via the spray-drying technology. Secondly, reduced magnetic Ni nanoparticles (NPs) were confined in the N-doped carbon microspheres after pyrolysis treatment in the H2/Ar atmosphere. Duo to the existence of melamine, the distribution of Ni NPs and related EM parameters of Ni@C microspheres were efficiently regulated to seek the well impedance matching and EM responded ability. As results, as-synthesized Ni@C microspheres exhibited the minimum reflection loss (RLmin) of −48.2 dB and effective absorption bandwidth (EAB) of 5.7 GHz, covering almost Ku-band. This research represents a significant advancement in the development of magnetic-dielectric composite microspheres with superior absorption capacity, and it also provides a large-scale preparation strategy for electromagnetic wave absorbing materials.

Ultralight and rigid PBO nanofiber aerogel with superior electromagnetic wave absorption properties

Polymer-based aerogels are emerging as promising candidates for lightweight and high performance electromagnetic (EM) wave absorption materials. In this study, an ultralight and rigid poly(p-phenylene benzobisoxazole) nanofiber (PNF) based composite aerogel with excellent EM wave absorption performance was fabricated with cobalt-nickel alloy (CoNi) nanoparticles and carbon nanotubes (CNTs) as magnetic and conductive fillers, respectively. A CNT/PNF composite aerogel was first prepared through a sol-gel and freeze-drying method, and then CoNi nanoparticles were introduced therein through hydrothermal reaction and thermal annealing to obtain the CoNi/CNT/PNF aerogel. CNTs and PNFs were interwoven and constructed a three-dimensional conductive/magnetic cage-like skeleton structure decorating with magnetic CoNi nanoparticles. The cage-like skeleton structure allowed the dissipation of EM waves through multiple mechanisms encompassing conduction loss, magnetic loss, multiple reflection, scattering, and absorption. When its thickness was 4 mm, the CoNi/CNT/PNF aerogel showed a minimal reflection loss of −44.7 dB (at 6.88 GHz), and its broad effective absorption bandwidth covered the entire X-band and Ku-band and most of the C-band (12.32 GHz, from 5.68 GHz to 18 GHz). In addition, the rigid aerogel exhibited an ultralow density (0.107 g/cm3), excellent thermal insulation, and flame retardancy, demonstrating its potential application as a high-performance EM wave absorption material in the fields of aerospace and national defense.

Enhanced electromagnetic wave absorption performance of Ta₄C₃Tx MXenes with optimized interlayer spacing via hydrofluoric acid etching

Ta4C3Tx MXene, a novel two-dimensional material, shows significant application potential for electromagnetic wave (EMW) absorption because of its unique layered structure and high conductivity. In this study, hydrofluoric acid etching was used to obtain Ta4C3Tx MXenes with varying interlayer spaces by adjusting the etching duration, which enhanced the EMW absorption performance. The impact of interlayer spacing on the EMW absorption performance of Ta4C3Tx MXene was systematically evaluated for the first time. The results show that the sample etched with hydrofluoric acid for 48 h (S2-48 h) exhibited the best EMW absorption performance. For S2-48 h, the optimal reflection loss (RL) value was −33.53 dB at a frequency of 9.74 GHz and a thickness of 1.4 mm. In addition, the widest effective absorption bandwidth was 2.97 GHz (10.73–13.7 GHz), which was achieved at a frequency of 11.72 GHz and a thickness of 1.2 mm. This outstanding performance is mainly attributed to good impedance matching and multiple loss mechanisms induced by the etching process, including conduction loss, dipolar polarization, interfacial polarization, and multiple RLs. Furthermore, this research expands the application potential of two-dimensional MXene materials in EMW absorption.

“Two birds one stone” strategy to integrate electromagnetic wave absorption and self-anticorrosion in magnetic nanocomposites with double-shell hollow structure

Magnetic metal has broad application prospects in the field of electromagnetic wave (EMW) absorption due to its excellent dielectric and magnetic properties. However, high density and poor chemical stability constrain their development potential. The combination of magnetic metals with other lightweight carbon materials is an effective solution. In this work, magnetic nanoparticle fiber composites were prepared by electrostatic spinning and high-temperature annealing processes. By adjusting the preparation process and annealing temperature, Co/Co7Fe3/CF-800 fiber composites containing double-shell hollow structured nanocubes were cleverly synthesized. The material is mixed with paraffin wax and has a minimum reflection loss (RL) of –52.14 dB and a maximum effective absorption bandwidth (EAB) of 6.16 GHz at a load of 10 wt%. By analyzing the electromagnetic parameters of the material, it was demonstrated that the material absorbs EMW through the synergistic effect of dielectric and magnetic losses. Electrochemical testing in a simulated seawater environment demonstrated that the material also has a degree of self-anticorrosion capability. This work provides new strategies for designing materials with excellent electromagnetic wave absorption and self-anticorrosion properties.

Performance evaluation of vehicular communication in terahertz band

Abstract The Terahertz (THz) band is seen as one of the potentially essential technologies to meet the data throughput requirements of terabits per second (Tbits) in future networks. Considering vehicular communication in particular, the current vehicular communication technologies cannot cope with the rapidly increasing data traffic. To deliver increased capacity and data rate with reduced latency, new technologies and methodologies are therefore required. It is recognized that one possible technology to meet these needs is THz technology. Since the change in distance between vehicles due to their speed affects THz communication, channel modeling was carried out for single-lane and multi-lane vehicular communication scenarios in this study. The system’s performance was also examined. Performance metrics were determined as path loss, signal-to-noise ratio (SNR), capacity and bit error rate (BER). While performing these analyses, the absorption of THz waves is taken into account and the High-Resolution Transmission Molecular Absorption Database (HITRAN) was used to model it. As a result, the most appropriate circumstances for successful vehicular communication have been identified and studied.

Facile manufacturing of carbon nanotube/ZIF-67-derived cobalt composite aerogel with high-efficiency electromagnetic wave absorption

Developing high-efficiency electromagnetic wave (EMW) absorbers by designing dielectric/magnetic components and microstructure in a straightforward, scalable method is highly desirable yet challenging. Here, we introduce a novel hierarchical composite aerogel-based EMW absorber composed of conductive carbon nanotubes (CNTs) and magnetic metal-organic framework (MOF) derivatives, integrated with sustainable cellulose nanofibers (CNF) derived carbon. This composite was prepared using a scalable freeze-casting followed by carbonization approach. Freeze casting enabled the creation of porous monoliths with high specific surface areas and customizable pore sizes and porosities, crucial for enhancing EMW reflection and scattering. Carbonization enhanced composite conductivity and stabilized the cobalt (Co)/carbon nanoparticles derived from ZIF-67 within the carbon matrix. CNF-derived carbon facilitated the efficient integration of ZIF-derived Co nanoparticles and CNTs, resulting in a robust 3D aerogel structure. The synergistic effects of CNT conductive paths and Co nanoparticles' magnetic losses provided an efficient route to enhance EMW absorption. Moreover, the creation of numerous heterogeneous interfaces augmented polarization losses, significantly enhancing EMW loss capability. Remarkably, the composite achieved outstanding EMW absorption, with a minimum reflection loss of -71.03 dB at a filling ratio of merely 10 wt.% and an effective absorption bandwidth of 4.64 GHz, comparable to leading EMW absorbers reported to date.

Construction of a highly ordered SiC nanofiber@C fiber heterojunction hybrid with a fuzzy grass-like structure for enhanced microwave absorbing performance

Carbon fibers (Cf) materials with excellent dielectric loss are increasingly attracting attention in the field of microwave absorption. However, the inherent high conductivity of carbon materials usually causes impedance mismatch, which seriously limits their widespread applications in the field of electromagnetic wave (EMW) absorption. To solve this problem, a highly ordered SiC nanofiber@C fiber (SiCnf@Cf) heterojunction hybrid with a fuzzy grass-like structure was fabricated through a simple chemical vapor deposition (CVD) method. Providing a heterogeneous interface on the surface of carbon fibers not only improves their impedance matching capability but also enhances their interfacial loss capability. As a result, a minimum reflection loss (RLmin) for SiCnf@Cf heterojunction hybrid is −44.04 dB at 13.6 GHz with a thickness of 1.2 mm, and a maximum effective absorption bandwidth (EABmax) is 3.44 GHz with a thin thickness of 1.1 mm. Furthermore, it also exhibits outstanding thermal insulation performance, which make it a potential candidate for heat-insulating applications. And due to its lightweight and soft characteristics, it perfectly meets the needs of wearable flexible absorbing materials. Therefore, this study not only provides a straightforward for preparing EMW-absorbing materials with exceptional performance, but also offers a solution for improving the thermal stability of the carbon-based material.

Gradient-structured SiCf/SiC hybrid woven metamaterials with superior broadband absorption and high-load bearing

SiCf/SiC composites provide a possibility to achieve the structure-function integration of military stealth materials used for aircraft tail. However, how to overcome narrow-band electromagnetic wave (EMW) absorption remains challenging. Herein, based on the adjustable permittivity of SiC fibers and the flexible design of woven structures, a gradient-structured SiCf/SiC hybrid woven metamaterial (GHWMM) is engineered with three different permittivity SiC fibers. The absorbing properties and mechanisms of the GHWMM were studied by combining experiment and simulation. Benefiting from the synergistic effect of strong dielectric loss, structural loss, and impedance matching, the GHWMM harvests an average reflection loss (RL) of −12 dB (93.7 % absorptivity), with an effective absorption bandwidth (EAB, RL ≤ −10 dB) of up to 10.7 GHz in the 4–18 GHz. Surprisingly, at high temperature of 1000 °C, the GHWMM still exhibits a RL below −5 dB in most frequency bands. Moreover, the GHWMM displays excellent wide-angle incidence characteristics, while possessing a remarkable flexural strength of 226.4 MPa. This work lays a foundation for the renewal of textile structures and the preparation of large-size assemblies, which holds promising prospect for application in the field of aircraft hot end components.

Unlocking versatile capabilities: Mixed-valence decavanadate aerogels for boosting radar, infrared, and thermal stealth

Multifunctional compatible stealth materials have emerged as the focal point of contemporary protection technology research and vanadium-based nanomaterials play a pivotal role in the development of advanced stealth materials. Here, a compatible stealth aerogel is successfully synthesized by employing mixed-valence decavanadate as the vanadium oxide (VOx) molecular model. Ultralight {VⅣVV9}/MXene aerogel (0.0429 g cm–3) exhibits exceptional radar stealth performance with a minimal reflection loss (RLmin) of −57.74 dB (99.9998% EMW absorption) and a significantly superior radar cross section reduction value of 26.77 dB m2. The aerogel's exceptional properties, including a low infrared (IR) emissivity (0.479) and a low thermal conductivity of (32.30 mW m–1 K–1), are crucial for enabling compatibility with IR and thermal stealth technologies. The presence of a mixed-valence polyoxovanadate cluster leads to an increase in the Schottky barrier and enhances magnetic properties, consequently boosting interfacial polarization and contributing to magnetic losses during electromagnetic wave (EMW) absorption. Consequently, altering the number of valence electrons significantly enhances the compatible stealth capabilities. These findings contribute significantly to our comprehension of how microstructure impacts EMW absorption processes and provide a basis for further research into the development of VOx-based compatible stealth materials.

FDTD simulation of beamforming shape of a woolly horseshoe bat (Rhinolophus luctus)

Abstract The practicality of the Finite-Difference Time-Domain (FDTD) method is employed to calculate the bat biosonar beamforming shape obtained from the three dimensional (3D) digital model of a woolly horseshoe bat (Rhinolophus luctus), as well as to acquire the nearfield sound pressure distribution of the transient sound field. The multiple sound pressure amplitude can be obtained by Fourier transform of the instantaneous sound pressure in the nearfield FDTD region. According to Kirchhoff integral, the far field normalized directivity pattern is obtained. The single point source is positioned at the center of the computational region, which is surrounded by four different number of perfectly matched layer (PML). The FDTD method is utilized to calculate the absorption of waves by the PML. The trustworthiness of the algorithm is authenticated by the outcomes. It demonstrates that FDTD can produce satisfactory outcomes for biosonar calculations on the woolly horseshoe bat.

Multifunctional seamless meta-sandwich composite as lightweight, load-bearing, and broadband-electromagnetic-wave-absorbing structure

Engineered porous geometries composed of low-density lossy materials are promising as broadband absorbers due to their tunable structural attenuation that can selectively manipulate electromagnetic (EM) waves. However, the exposed cellular architectures require mechanical reinforcement and additional packaging. Here, we present a multifunctional meta-sandwich structure as one seamlessly integrated component composed of functional faceplates and dielectric lossy material-based octet-truss geometries toward a lightweight, load-bearing, and high-performance broadband EM wave absorber. EM responses are explored in the 4–18 GHz range by varying material combinations and multilayers of the upper-lower faceplates and the octet-truss core, elucidating the absorbing mechanisms of meta-sandwich structures. Multi-material 3D printing that streamlines the production of the seamless meta-sandwich composite into a single step implements the devised design that simultaneously excel in EM wave absorption and mechanical functionalities. The fabricated composite in a thin, single-layer structure comprising a transmitting upper faceplate, a dielectric lossy core, and a reflecting lower faceplate, achieves an average absorption rate of 95.0 % and a broadband reflection loss (≤-10 dB) over the entire measured bandwidth. Furthermore, flexural testing confirms superior bending resistance compared to conventional honeycomb structures. The multi-materials meta-sandwich design will inspire versatile multifunctionalities enabled by rationally combining mechanical metamaterials and functional housing.