Reflection Loss Research Articles

AlN/FeNi Microwave-Attenuating Ceramics with High-Efficiency Thermal Conductivity and Microwave Absorption

The integration, miniaturization, and high frequency of microwave vacuum electronics put forward higher requirements for heat-conducting and wave-absorbing integrated materials. However, these materials must balance the dispersion and isolation of wave-absorbing components to optimize absorption while maintaining the continuity of thermal conductivity pathways with low defect rates and minimal interfaces. This presents a significant challenge in achieving both high thermal conductivity and efficient wave absorption simultaneously. Here, AlN/FeNi microwave-attenuating ceramics were synthesized via non–pressure sintering in a nitrogen atmosphere. The influence of FeNi content (0–20 wt%) on the density, phase composition, microstructure, microwave-absorption properties and thermal conductivity of the composites was investigated. AlN/FeNi composites consist primarily of an AlN phase with FeNi0.0578, Fe, AlYO3, and Al5Y3O12 as secondary phases, and the microstructure is uniform and dense. As the FeNi content rises from 0 to 20 wt%, the density of the composites sintered at 1800 °C × 2 h increases from 3.3 to 3.7 g/cm3. Their X-band (2–18 GHz) dielectric constant goes up from 6.5 to 8.5, the dielectric loss factor rises from 0.1 to 0.9, and thermal conductivity diminishes from 130 to 123 W/m·K. Upon reaching an FeNi content of 20 wt%, the composite achieves a minimum reflection loss of −39.1 dB at 9.5 GHz, with over 90% absorption across an effective absorption bandwidth covering 2.5 GHz. It exhibits excellent impedance matching, electromagnetic wave-attenuation properties, a relative density of 98.6%, and a thermal conductivity of 123 W m−1 K−1. The prepared AlN/FeNi composites, with integrated outstanding microwave-absorption capabilities and thermal conductivity, holds great promise for applications in 5G communications, aerospace, and artificial intelligence.

Radar‐Terahertz‐Infrared Compatible Stealth Coaxial Silver Nanowire@Carbon Nano‐Cable Aerogel

AbstractAchieving multi‐spectrum compatible stealth in radar‐terahertz‐infrared bands with robust performance has great prospects for both military and civilian applications. However, the progress of materials encounters substantial challenges due to the significant variability in frequency coupling properties across different electromagnetic wave bands. Here, this work presents the design of a multi‐scale structure and fabricates a lightweight aerogel (silver nanowire@carbon, AgNW@C) consisting of a regular coaxial nano‐cable, with silver nanowire as the core and amorphous‐graphitized hybrid carbon as the outer‐layer. The design utilizes the one‐dimensional conductive network and electric coupling heterogeneous interface, the low infrared emission of silver nanowires, and the thermal insulation caused by three‐dimensional pore structure found in aerogels. This conception achieves the long‐standing goal of multi‐spectrum compatible stealth in an integrated material. The AgNW@C aerogel exhibits an optimal reflection loss of −66.50 dB and an effective absorption bandwidth of 8.80 GHz in the gigahertz band, while an average total shielding performance of 71.92 dB and over 50.00 dB reflection loss in the terahertz band. Furthermore, the AgNW@C aerogel demonstrates remarkable thermal infrared stealth capabilities with a low infrared emissivity of 0.28 and thermal insulation up to 150 °C under 200 °C. These exceptional multispectral stealth properties allow the aerogel for potential applications in military camouflage technology and electromagnetic protection.

Radar-Terahertz-Infrared Compatible Stealth Coaxial Silver Nanowire@Carbon Nano-Cable Aerogel.

Achieving multi-spectrum compatible stealth in radar-terahertz-infrared bands with robust performance has great prospects for both military and civilian applications. However, the progress of materials encounters substantial challenges due to the significant variability in frequency coupling properties across different electromagnetic wave bands. Here, this work presents the design of a multi-scale structure and fabricates a lightweight aerogel (silver nanowire@carbon, AgNW@C) consisting of a regular coaxial nano-cable, with silver nanowire as the core and amorphous-graphitized hybrid carbon as the outer-layer. The design utilizes the one-dimensional conductive network and electric coupling heterogeneous interface, the low infrared emission of silver nanowires, and the thermal insulation caused by three-dimensional pore structure found in aerogels. This conception achieves the long-standing goal of multi-spectrum compatible stealth in an integrated material. The AgNW@C aerogel exhibits an optimal reflection loss of -66.50 dB and an effective absorption bandwidth of 8.80 GHz in the gigahertz band, while an average total shielding performance of 71.92 dB and over 50.00 dB reflection loss in the terahertz band. Furthermore, the AgNW@C aerogel demonstrates remarkable thermal infrared stealth capabilities with a low infrared emissivity of 0.28 and thermal insulation up to 150 °C under 200 °C. These exceptional multispectral stealth properties allow the aerogel for potential applications in military camouflage technology and electromagnetic protection.

Bamboo-Inspired Hierarchically Hollow Aerogel MXene Fibers with Ultrafast Ionic Channels and Multiple Electromagnetic Wave Attenuation Routes Toward High-Performance Supercapacitors and Microwave Absorption.

2D materials feature large specific surface areas and abundant active sites, showing great potential in energy storage and conversion. However, the dense, stacked structure severely restricts its practical application. Inspired by the structure of bamboo in nature, hollow interior and porous exterior wall, hollow MXene aerogel fiber (HA-Ti3C2TX fiber) is proposed. Owing to continuous porous microstructure and optimized hollow cavity, this fiber possesses large accessible area to ions and abundant structural defects, leading to a fast charge transfer kinetics and high faradic activity. Consequently, the HA-Ti3C2TX fiber exhibits exceptional gravimetric capacitance of 355 F g-1. Besides, the solid-state asymmetric fiber-shaped supercapacitors (FSCs) display a high capacitance of 276 F g-1 and energy density of 9.58 Wh kg-1. Additionally, the HA-Ti3C2TX fiber delivers outstanding electromagnetic wave (EMW) absorption performance with a minimum reflection loss of -52.39 dB and the effective absorption bandwidth up to 4.6 GHz, which is attributed to multiple reflection paths, strong dielectric loss from this hollow and porous structure. This novel design of hollow fiber provides a new reference for the construction of advanced fibers for energy storage and EMW absorption materials.

Monolayer Interfacial Assembly toward Two‐Dimensional Mesoporous Heterostructure for Boosting Wave Absorption

AbstractMicrowave absorption materials play a key role in various fields, including military stealth, human safety protection, and so on. Construction of 2D mesoporous heterostructures is an attractive approach to enhance wave‐absorbing ability, while it is still a great challenge. Herein, 2D mesoporous carbon‐MXene‐carbon heterostructures (MCMCH) with channels parallel to surface are successfully prepared via a monolayer interfacial assembly strategy. Through the precise adjustment and polymerization, cylindrical micelles orderly monolayered assemble on both surfaces of 2D MXene nanosheets, resulting in 2D switch‐like polydopamine‐MXene‐polydopamine nanosheets, and 2D MCMCH are finally generated by further calcination. Due to the excellent dielectric polarization relaxation and conductive loss, MCMCH achieves the strongest reflection loss of −54.2 dB at a thickness of only 1.5 mm. The presence of mesochannels not only introduces air with a low permittivity for optimal impedance matching, but also further extends the attenuation path of the incident electromagnetic wave. The maximum radar cross‐section reduction of 26.9 dB m2 is achieved for the MCMCH compared to the perfect electric conductor. This work provides a reference for surface engineering based on 2D mesoporous heterostructures to enhance the microwave absorption performance.

Rapid electrothermal upcycling hexachlorobutadiene (HCBD) polluted distillation residue into turbostratic graphene for enhanced electromagnetic wave absorption.

The trichloroethylene production industry generates high-boiling-point solid residues during rectification, which contain high concentrations of chlorinated contaminants, particularly hexachlorobutadiene (HCBD). Traditionally, these distillation residues are managed through co-incineration or landfilling, leading to environmental and economic challenges. In this study, we present a rapid and environmentally friendly electrothermal approach for both detoxifying and upcycling distillation residue into graphene-based electromagnetic wave (EMW) absorbing materials. By employing a DC power pulse discharge with a 10 s duration, we achieved over 99 % HCBD degradation efficiency. Characterization results indicate that the thermal shock transforms the distillation residue into high-value turbostratic pulse graphene (tPG). This tPG, featuring a unique structure, demonstrates substantial potential as an EMW absorber, with an effective absorption bandwidth of 3.9 GHz and a reflection loss of -42.0 dB at a minimal matching thickness of 1.6 mm. The method offers a sustainable, cost-effective solution for hazardous waste management, combining rapid processing with high-value material production.

Full-Spectrum Mechanochromic Photonic Films with Large Interparticle Distance.

Non-close-packed crystalline arrays of colloidal particles in an elastic matrix exhibit mechanochromism. However, small interparticle distances often limit the range of reversible color shifts and reduce reflectivity during a blueshift. A straightforward, reproducible strategy using matrix swelling to increase interparticle distance and improve mechanochromic performance is presented. Photonic composites are initially prepared with silica particle arrays embedded in an elastomer matrix at volume fractions of 0.35-0.5. To increase interparticle distance, the composites are immersed in an elastomer-forming monomer, causing the matrix to swell, followed by photopolymerization, thereby producing liquid-free composites. The degree of swelling is controllable up to 3.16, depending on monomer choice, matrix volume fraction, and crosslinking density. The process can be repeated to further increase swelling up to 10.36. This method can reduce the volume fraction of silica particles from 40% to 3.8%, while interparticle distance increases from 53 to 257nm. The swollen photonic composites exhibit a full visible spectrum under compression, while minimizing reflectivity loss. This allows red-colored photonic composites to be transformed into vivid multicolor patterns when compressed with stamps featuring spatial height variations.

A Dual‐Band Dual‐Polarized Rectenna for Efficient RF Energy Harvesting in Battery‐Less IoT Devices With Broad Power Range

ABSTRACTThe demand for maintenance‐free, battery‐less IoT devices, driven by sustainable Industry 4.0 practices, necessitates efficient RF energy harvesting solutions. Addressing the limitations of single‐frequency harvesting, a novel dual‐band, dual‐polarized rectenna operating at 3.6 GHz and 5.8 GHz is proposed. The antenna resonates at 3.6 GHz with linearly polarized (LP) characteristics and 5.8 GHz with circularly polarized (CP) characteristics with impedance bandwidth (IBW) of 2.2% and 5.63%, respectively, achieving a gain of 4.85 dBi and 6.75 dBic, respectively. A rectenna consists of an antenna at the front end and an RF‐DC rectifier at the backend. This approach maximizes power conversion efficiency by minimizing impedance mismatches and reflection losses and mitigates interference between the dual bands within the rectifier circuitry. The rectifier achieves peak efficiencies of 65.5% at 3.6 GHz with a 3 dBm input and 44% at 5.8 GHz with a −1 dBm input, both with 2KΩ load. Efficiency exceeds 30% at 3.6 GHz for an input range from −10 to 6.5 dBm and exceeds 20% at 5.8 GHz for an input range from −13 to 3 dBm. These design considerations enable reliable harvesting of ambient RF energy across a range of −20 to 20 dBm, enabling continuous IoT device operation. Our measurements confirm the design's effectiveness in converting low‐power RF signals into usable energy, supporting sustainable and autonomous IoT deployments at 3.6 and 5.8 GHz.

High-Performance Thermoelectric Composite of Bi2Te3 Nanosheets and Carbon Aerogel for Harvesting of Environmental Electromagnetic Energy.

Intensifying the severity of electromagnetic (EM) pollution in the environment represents a significant threat to human health and results in considerable energy wastage. Here, we provide a strategy for electricity generation from heat generated by electromagnetic wave radiation captured from the surrounding environment that can reduce the level of electromagnetic pollution while alleviating the energy crisis. We prepared a porous, elastomeric, and lightweight Bi2Te3/carbon aerogel (CN@Bi2Te3) by a simple strategy of induced in situ growth of Bi2Te3 nanosheets with three-dimensional (3D) carbon structure, realizing the coupling of electromagnetic wave absorption (EMA) and thermoelectric (TE) properties. With ultra-low thermal conductivity (0.07 W m-1 K-1), the CN@Bi2Te3 composites achieved a minimum reflection loss (RL) of 51.30 dB and an effective absorption bandwidth (EAB) of 6.20 GHz at an optimal thickness of 2.8 mm. Additionally, under a temperature gradient of 80 K, the flexible thermoelectric generator (FTEG) system generates a maximum output power of 42.2 μW. By absorbing 2.45 GHz microwaves to build the temperature difference, the EMA-TE-coupled device achieves an optimal Uoc of 38.4 mV, a short-circuit current of 1.03 mA, and an output power of 9.87 μW upon a radiation time of 50 s. This work establishes a potential pathway for further recycling electromagnetic energy in the environment, which is also promising for the preparation of large-area flexible EM to electrical energy conversion devices.

Gene-Implanting by a Porphyrin Derivative to Establish Quasi-antennas into the Carbon Microspheres toward Superior Microwave Absorbing/Shielding Performance.

Carbon microspheres (CMSs) are recognized as highly effective microwave absorbers due to their exceptional wave absorption properties. In this study, 5,10,15,20-tetrakis(4-aminophenyl)porphyrin, a metamaterial, was chemically bonded to CMSs─considered a conjugated carbon structure─using a 1,3-dibromopropane linker to explore the synergistic properties and microwave absorption capabilities of the synthesized composite. The synthesized structures were characterized by using X-ray diffraction, FE-SEM, Fourier transform infrared, diffuse reflectance spectroscopy, and VNA analyses. Remarkably, the gene-modified microwave absorber demonstrated a maximum reflection loss of -105.58 dB at 22.93 GHz, with an ultrathin thickness of only 0.50 mm. When the architected samples were blended with poly(methyl methacrylate), a practical polymer, they exhibited a broad efficient bandwidth across the entire K-band, coupled with moderate shielding effectiveness, making them ideal for mitigating electromagnetic pollution in everyday life. This study offers inspiration for researchers to fabricate and design new enhanced microwave absorbers for a range of applications.

Bio-derived graphitic carbon microspheres: A green approach for high-frequency microwave absorption

Bio-derived carbon materials have emerged as a sustainable alternative to non-renewable petroleum-based carbon sources, thanks to their reproducibility and environmental benefits. There is a strong demand for developing and efficiently utilizing carbon-based microwave absorbing materials (MAMs) that are lightweight, require low filler loading, and offer broadband absorption for electromagnetic wave (EM) applications. In this context, we successfully synthesized uniform carbon microspheres from the natural precursor turpentine oil using the chemical vapor deposition (CVD) technique at various temperatures. The sample prepared at 1000 °C (GC-1000) exhibited a uniform carbon microsphere morphology, as confirmed by XRD and Raman spectroscopy, and demonstrated extremely good microwave absorption properties. With a low filler loading of just 5 wt%, the GC-1000 sample achieved a minimum reflection loss (RL) of −39.77 dB at 10.21 GHz and an effective absorption bandwidth of 2.51 GHz at a matching thickness of only 2.8 mm. Additionally, this sample showed a total shielding effectiveness (SET) of −44.74 dB, surpassing the threshold required for commercial applications. The graphitic phase formation, confirmed by XRD and Raman analysis, acts as a conductive trap for electromagnetic radiation, and the high surface area of the uniform carbon microspheres facilitates multiple internal reflections, enhancing overall microwave absorption performance in the X-band region. Our lightweight, durable, bioderived carbon microspheres, synthesized through a cost-effective and scalable process, show significant potential for EM wave absorption in military and electromagnetic compatibility (EMC) devices.

Structural, electronic, mechanical, optical and magnetic properties of RhNbZ (Z = Li, Si, As) Half-Heusler compounds: a first-principles study

Abstract Structural, mechanical, electronic, optical and magnetic properties of the cubic RhNbZ (Z = Li, Si, As) half-Heusler compounds is reported using density functional theory (DFT) as implemented in quantum espresso simulation package. Structurally, the compounds are most stable when they are in type I atomic arrangement. Studies of mechanical properties indicate that all the three compounds are ductile in nature and mechanically stable. Calculations of electronic band structure and density of states (DOS) affirm that RhNbSi is a semi-conductor with an indirect band gap of 0.662 eV and 1.0095 eV from generalized gradient approximation (GGA) and GGA+U approaches respectively, where U is Hubbard parameter, RhNbLi has metallic property under both GGA and GGA+U approaches whereas RhNbAs has metallic nature under GGA prediction but it has half-metallic property under GGA+U approach, a property which is essential for spintronic applications. Optical parameters such as dielectric function, reflectivity, refractive index, extinction coefficient, absorption coefficient, optical conductivity and electron energy loss were estimated in the photon energy range of 0–40 eV. Results from these properties calculations reveal that both absorption coefficient and optical conductivity have maximum values whereas electron energy loss has minimum value in the lower energy ranges which show that the materials under our study can be considered as potential candidates for optoelectronic applications. From magnetic property calculations, RhNbSi is predicted to be nonmagnetic material but RhNbLi and RhNbAs have magnetic nature.

Hierarchical core-shell transitional metal chalcogenides Co9S8/ CoSe2@C nanocube embedded into porous carbon for tunable and efficient microwave absorption

In the domain of electromagnetic (EM) wave absorbing materials, the selection of suitable components and microstructures is an effective approach for designing the intense coupling of wave impedance and EM dissipation. In this study, we have successfully fabricated a double-carbon modified Co9S8/CoSe2 nanocube, where the core-shell Co9S8/CoSe2@C cube was anchored onto porous carbon (PC). The existence of three-dimensional (3D) porous carbon and the fabrication of Co9S8/CoSe2@C distributed on carbon nanosheets contribute to the improvement of conduction, magnetic losses, and the optimization of impedance matching. Substantial heterogeneous interfaces are generated between Co9S8, CoSe2, carbon shells, and PC, leading to extensive interfacial polarization and facilitating the transformation of EM energy into thermal energy. The abundant defects, S and Se vacancies in carbon component can act as polarization centers, inducing dipolar polarization and thus increasing the electromagnetic wave (EMW) loss. The Co9S8/CoSe2@C@PC exhibits the best microwave absorption properties, with a minimum reflection loss (RLmin) of −64.1 dB at 2.5 mm and an effective absorption bandwidth (EAB) of 6.3 GHz. The High-Frequency Structure Simulator results indicate the RCS values of the samples within the range of -90 °C < θ < 90 °C are lower than -20 dB m2, which can achieve almost full-angle coverage in the actual environment. This research offers inspiration and strategies for the design and synthesis of multi-component magneto-electric composites based on transitional metal chalcogenides.

Design and fabrication of 2.5D Janus hybrid woven SiCf/SiC metamaterials for broadband absorption and high load-bearing

SiCf/SiC composites have been widely used in hot end parts of aircraft because of advantages of high strength, high temperature resistance and oxidation resistance. However, their narrow-band electromagnetic (EM) waves absorption features limit the realization of structure–function integration. To break this limitation, a 2.5D Janus hybrid woven SiCf/SiC absorbing metamaterial (JHWMM) composed of three different permittivity SiC fibers is proposed, and the genetic algorithm is used to optimize the thickness and permittivity of each layer. Further, the absorption properties and mechanisms were studied by combining experiment and simulation. Compared with the 2.5D woven SiCf/SiC composite composed of only a single permittivity fibers, the effective absorption bandwidth (EAB, 11.2 GHz) of the JHWMM is increased by 2.7 times, and the average reflection loss (RL, −12.4 dB) increased by 1 times. Its excellent absorbing performance is attributed to the synergistic effect of strong structural loss, dielectric loss and excellent impedance matching. In addition, the JHWMM also exhibits good wide-angle (0°-40°) absorption characteristics and excellent load-bearing properties (the bending strength is 222.3 MPa). The 2.5D Janus hybrid woven structure proposed in this study provides an important reference for the development of high-bearing, wide-absorbing and high-temperature absorbing materials for a new generation of aircraft, and has important engineering application value.

Hollow conductive polypyrrole microtubes as microwave absorbents with good seawater corrosion resistance

Conductive polymers materials with hollow micro/nanostructure due to their special electrical properties and corrosion resistance have potential applications in microwave absorption, especially in marine environment. Herein, one-dimensional hollow conductive polypyrrole microtubes (H-PPyM) were prepared by in-situ polymerization of pyrrole monomer with methyl orange (MO) as soft template and FeCl3 as oxidant based on structural regulation strategy. The morphology and conductivity of H-PPyM can be easily controlled by adjusting the content proportion of MO. The results indicated that the surface morphology of polypyrrole changed from random granular to microtubular and the conductivity also gradually rose with the content increase of MO. When the content proportion of MO was 0.25 g, the obtained H-PPyM-0.25 composites possed notable microwave absorption capacity, simultaneously achieving ultrabroad effective absorption bandwidth (EAB, 6.7 GHz) and strong reflection loss value (RL, -33.6 dB) at a thickness of 2.6 mm with the filling content of only 10 wt.%, respectively. Furthermore, the corresponding H-PPyM-0.25 products soaked in corrosive medium (3.5 wt% NaCl solution) for one month still displayed stable tubular hollow structure and excellent microwave absorption performance with RLmin of -43.8 dB and EAB of 6.2 GHz. The research results can not only help to understand the relationship among the morphology and microwave absorption of PPy, but also open a new avenue for preparing excellent seawater corrosion resistant microwave absorption materials.

Preparation and performance of porous carbon microwave absorber with high porosity from carbonized natural plant fibers

Herein, we present a novel fabrication approach to synthesize lightweight, highly porous, high-frequency microwave absorbers via temperature-induced manufacturing of 1D helical/chiral porous carbon fibers (HPCFs). This approach is unmatched in its effectiveness. Furthermore, this unique fabrication approach does not require pre-treatments such as activation, complex stripping-off processes, or harmful chemicals to generate the microwave absorber (MA). The MA with nanoscale/microscale structures, multidimensional 0 or 1D integration, helical/chiral configuration, and assorted loss mechanisms endow the absorber with exemplary microwave absorption capabilities. The maximum reflection loss (RLmax) of HPCFs-700-22.5% (700 and 22.5% correspond to the temperature at which biomass fiber get carbonized and the amount of filler material present) achieves -57.40dB RLmax at 15.20GHz with the wide effective absorbing bandwidth (EAB, RLmax ≤ -10 dB) of 5.40GHz (12.60-18.00GHz) and 2.47mm thickness. Notably, at a matching thickness of 2.60mm, the EAB improved to cover 12.00-18.00GHz (6.00GHz). Moreover, HPCFs-800-22.5 exhibit ultrawide EAB covers of 14.60-18.00GHz (3.40GHz), while RLmax surpasses -57.80dB at the matching thickness of 1.51mm. HPCFs-900-22.5% achieve RLmax of just -51.00dB with EAB of 5.40GHz (12.60-18.00GHz) at 14.90GHz, while the matching thickness of absorber is 2.22mm. The HPCFs with such exceptional microwave absorption properties shed light on the development economical and environmentally friendly MA with comparable microwave performances over exceptional EAB.

Enhanced, broad and thin low-frequency microwave absorption induced by proper magnetic anisotropy in polyhedral SmFeO3-encapsulated Sm2Fe17 nanoparticles

High permeability accompanied with large magnetic loss is considered as an effective strategy for achieving efficient low-frequency absorption. However, it remains a considerable challenge for synergistically improving the permeability and magnetic loss at low frequency range due to the proper magnetic anisotropy. In this study, arc discharge method is proposed to fabricate polyhedral core-shell structured Sm2Fe17 nanoparticles with averaged size of 160nm, in which SmFeO3 with averaged thickness of ~3.5nm works as dielectric shell. The frequency dependence of electromagnetic parameters of 20wt.% Sm2Fe17@SmFeO3 nanoparticles-paraffin composites have been studied at 2-18GHz. Natural resonance frequency reaches 6.64GHz. The real part and imaginary part of initial permeability is up to 2.42 and 0.76, respectively. The composite delivers the minimal reflection loss of -45.36dB at 3.2GHz with 3.0mm and the optimal effective absorption bandwidth of 2GHz (5.84-7.84GHz) with only matching thickness of 1.5mm. The superior low-frequency absorption performances are ascribed to the planar anisotropy field for providing high permeability and the polyhedral structure for suppressing natural resonance movement to mid-high frequencies. Furthermore, radar cross section simulations verify the great potential for practical applications. This work provides a valuable reference for designing microwave absorbers with merits of strong absorption, wide bandwidth and thin thickness in the low frequency range.

PVP-assisted MOF-derived Fe3O4/C powders for microwave absorption applications.

Metal-organic framework (MOF) derived porous Fe3O4/C powders were applied for absorption of microwaves in the frequency range of 1-18GHz. The effects of the polyvinylpyrrolidone (PVP) additive on the synthesis of MIL101-(Fe) precursor were studied by various characterization methods. By adding PVP, the impure hematite phase (α-Fe2O3) with magnetite phase (Fe3O4) was disappeared and the particular morphology was transformed to the porous rod-like, leading to the increase of specific surface area from 150 to 282m2/g. Furthermore, the saturation magnetization (Ms) of Fe3O4/C powders reached a maximum value of 47 emu/g at a proper amount of PVP. A thin absorber (2.6mm) made of 50wt% Fe3O4/C powders and 50wt % paraffine absorbed the whole of X frequency band (8-12GHz) with a minimum reflection loss of -20 dB at a matching frequency of 10GHz. Adjusting the permittivity and permeability parameters of the Fe3O4/C powders via adding PVP was responsible for their better microwave absorption performance.

Gd doped Cu-Ni-Zn nano ferrite absorbers for broadband microwave absorption: Physicochemical, electromagnetic, and reflection loss evaluations

Gd doped Cu-Ni-Zn nano ferrite absorbers for broadband microwave absorption: Physicochemical, electromagnetic, and reflection loss evaluations

Shape-Tunable Vanadium selenide/reduced graphene oxide Composites with Excellent Electromagnetic Wave Absorption Performance

The tunable energy gap and distinctive layered configuration of transition metal dichalcogenides (TMDs) has sparked considerable interest in their capabilities for electromagnetic wave absorption. As a significant TMD, vanadium selenide (VSe2) is characterized by a superior electrical conductivity (1 × 10-3 S/m) and an expanded interlayer distance, which are advantageous for electromagnetic wave absorption performance. Nevertheless, the current research on VSe2 in electromagnetic wave absorption is relatively limited. In this study, flower-like VSe2 and shape-tunable VSe2/reduced graphene oxide (rGO) composites were fabricated via a simple solvothermal method, and the effect of their morphology on electromagnetic wave absorption performances was investigated. The VSe2/rGO composites exhibited remarkable electromagnetic wave absorption properties at a thickness of 2.01 mm, with a reflection loss value (RL) of up to -79.50 dB, and an effective absorption bandwidth (EAB) of 5.2 GHz (1.45 mm). This research has identified a novel approach to the study of TMDs in the field of electromagnetic wave absorption.