Wave Absorption Research Articles

Modelling of ICRH slow wave propagation and absorption in Wendelstein 7-X stellarator

Abstract The propagation and absorption of the slow waves in the three-ion plasma of the Wendelstein 7-X stellarator have been investigated by ray tracing. The aim of the study is to obtain a qualitative notion of the penetration into the plasma and absorption of the wave excited by the potential difference between the antenna conductors and the antenna box. It has been discovered that the rays propagate along the magnetic field lines over a significant distance, up to 6 m, from the antenna. They weakly, to a depth of 0.1 m, penetrate into the plasma. Absorption of the slow waves by electrons does not lead to the generation of the currents capable of affecting the plasma equilibrium. Most of the slow waves are absorbed beyond the region of ion-ion hybrid resonance in the zone of cyclotron resonance of He3 ions at the periphery of the plasma. The ICRH of the three-ion W 7-X plasma will be used to heat He3 ions to high energies and simulate the confinement of alpha particles in an optimized stellarator configuration. The presence of a source of hot He3 ions, which are poorly confined, at the periphery of the plasma can affect the experimental results.

Construction of polymer-derived double transition metal compound/carbon matrix nanocomposites for efficient electromagnetic wave absorber

As typical dielectric materials, transition metal compounds have a broad potential in the field of stealth, but their application is still hampered by poor conductivity. In this study, based on the mechanism of electrostatic self-assembly of heteropolyacids and organic ligands, the electrostatic structures obtained after the introduction of different heteropolyacids into the conductive phase pyrrole are carbonized. On the one hand, the as-prepared transition metal compounds/carbon matrix nanocomposites produce synergistic effects and optimize impedance matching, and on the other hand, the formation of the abundant heterogeneous interfaces as well as the doping of the N, P heteroatoms induce the generation of interfacial polarisation and dipole polarisation, all of which provide the opportunities to produce composites with enhanced electromagnetic wave absorption properties. Unsurprisingly, the best synthesised sample, Mo2C/W2C/NPC, exhibits a significantly improved electromagnetic wave absorption performance, with an effective bandwidth of 5.7 GHz at a matched thickness of 2.5 mm, where the minimum reflection loss value of −54.5 dB is also achieved. The total effective bandwidth of the Mo2C/W2C/NPC-35 wt% is up to 10.5 GHz (7.3–17.8 GHz) via adjusting the matching thickness in the range of 1.7–3.5 mm. Therefore, this study reflects that dual transition metal compound/carbon based composite wave-absorbing materials provide a new material basis for the construction of high-performance absorption materials.

Lightweight and hierarchical carboxyl chitosan-derived carbon aerogel for electromagnetic wave absorber and heat insulation

In recent years, carbon aerogels derived from biomass have shown promising potential in electromagnetic wave (EMW) absorption field owing to their lightweight nature, controllable structure, environmental friendliness, and abundant pore structure. This study reports a novel type of carbon aerogels based on carboxyl chitosan (CCS) and graphene oxide (GO) with rich pores and a unique three-dimensional interconnected structure through solution mixing, freeze-drying, and pyrolysis process. The EMW absorption performances of the carboxyl chitosan/GO xerogel derived carbon aerogels (CGCAs) are adjusted by varying the content of graphene oxide (GO). The nitrogen elements inherent in chitosan can provide a large number of defects to the carbonized material, effectively capturing and attenuating EMW. Synthesized CGCAs show excellent EMW absorption performance with increasing GO content and the CGCA-6 exhibits the best performance. At a thickness of 1.7 mm, it has RLmin of −61.67 dB, and at a thickness of 1.5 mm, it has the widest effective absorption bandwidth (EAB) of 4.24 GHz (12.96–17.12 GHz). Additionally, under far-field conditions, at a thickness of 1.7 mm, the maximum radar cross-section (RCS) reduction relative to a PEC plate for the prepared CGCA-6 is 22.28 dB m2. Furthermore, the good thermal insulation capability exhibited by CGCA-6 makes it suitable for complex application scenarios. Therefore, this biomass-derived multi-functional carbon aerogel with excellent EMW absorption performance, radar stealth, infrared stealth, and thermal insulation capabilities has broad prospects for applications in EMW protection and aerospace fields.

Heterostructure engineering of N-doped Co@ carbon nanotubes toward broadband efficient electromagnetic absorption

The synergistic effect of magnetic loss and dielectric loss, as well as the reasonable construction of microstructure, have a significant effect on improving the absorption performance of electromagnetic wave absorbers. In this paper, N-doping Co@ carbon nanotubes (NCC) composites are successfully grown in situ on cobalt particles using a cobalt source as a catalyst. The metal particle Co is encapsulated within the carbon nanotubes and N is doped in the carbon lattice. This special structure introduces a large number of heterogeneous interfaces and defects, leading to optimized impedance matching and strong electromagnetic attenuation. The results showed that the minimum reflection loss is −69.33 dB for NCC800-1 with a thickness of 1.6 mm, and NCC900-4 possesses the widest effective absorption bandwidth of 7.70 GHz at a thickness of 2.1 mm with other NCC composites. Furthermore, the radar scattering cross section simulation results confirm that the prepared absorbing coatings can well suppress radar waves in different directions. The outstanding absorption performance is attributed to the defects and heterogeneous interfaces in the cobalt-catalyzed carbon nanofibers, the conductive network formed by carbon fibers, and the synergistic effects of magnetic and dielectric losses. This work presents a novel engineering approach for synthesizing absorbers with multiple loss mechanisms and heterogeneous structures, offering a promising pathway for the development of high-performance electromagnetic wave absorbing materials.

A novel high-entropy perovskite Ba(Zn0.2Yb0.2Ta0.2Nb0.2V0.2)O3 ceramic with excellent Electromagnetic wave absorption properties

In order to solve the increasingly serious electromagnetic wave pollution, the preparation of high-performance electromagnetic wave absorbing (EWA) materials has been very urgent. High-entropy ceramics have a good prospect in the field of EWA materials due to the unique effect brought by its multi-component elements. Therefore, in this study, the composition of high-entropy ceramics was designed by utilizing the Goldschmid tolerance factor. Then the high-entropy perovskite Ba(Zn0.2Yb0.2Ta0.2Nb0.2V0.2)O3 ceramic (BZO) with high EWA performance was prepared by high-temperature solid-phase method. The EWA mechanism of the material was explored based on the phase composition, microstructure and electromagnetic parameters of the samples. Good impedance matching and better attenuation ability were obtained for BZO-1100 due to the crystallographic transition and interface increase. As a result, BZO-1100 achieves excellent EWA performance at a thickness of 2.12 mm, with a minimum reflection loss (RLmin) of −54.09 dB and an effective absorption bandwidth (EAB) of 2.81 GHz in the X-band. In addition, the possibility of the practical application of the BZO high-entropy ceramics is verified by electric field distribution simulations and RCS simulations. This study provides a valuable reference for the design of high-performance high-entropy perovskite ceramic absorber materials.

Biological template hydrothermal synthesis of hollow La-doped one-dimensional CaMnO3 fibers and their enhanced microwave absorption performance

The advancement of military technology, 5G communication, and electronic equipment has increased the demand for efficient electromagnetic wave absorption materials. Calcium manganate (CaMnO3) is a commonly used dielectric absorber due to its excellent dielectric polarization effect. However, traditional ceramic materials like CaMnO3 have low conductivity, making it difficult to achieve impedance matching and electromagnetic loss simultaneously. In this work, to address this issue and create ideal wave-absorbing materials, one-dimensional La-doped CaMnO3 materials were synthesized using a simple biological template hydrothermal method. By studying the relationship between doping content and electromagnetic parameters, it was found that the La-doped CaMnO3 material exhibited excellent electromagnetic wave absorption properties, with a minimum reflection loss (RLmin) of −73.62 dB and a maximum effective absorption bandwidth of 3.3 GHz in the X-band. The introduction of La elements, which have different electronegativities from Ca ions, altered the electron cloud distribution in the sample, leading to the formation of electric dipoles that disrupt charge distribution and dissipate electromagnetic waves. The dielectric loss in fibrous La-doped CaMnO3 is mainly due to interfacial polarization. The fibrous structure allows for increased contact area with the air medium, while the porous structure introduces air bubbles that alter the dielectric properties between the sample and the air medium. This not only enhances impedance characteristics to some extent but also triggers interfacial polarization. Both of these factors help improve the material's ability to absorb electromagnetic waves. The successful creation of this one-dimensional absorbing material opens up possibilities for developing new one-dimensional absorbing materials using a straightforward method.

Design and theoretical analysis of near-infrared multiband metamaterial absorber with concentric sub-resonators for solar applications

Metamaterial absorbers with multiple frequency bands can be designed by stacking sub-resonators vertically or arranging them co-planarly. However, to increase the number of absorption peaks, we often need more sub-resonators. Therefore, a study explores dynamic infrared multiband metamaterial absorbers to enhance electromagnetic wave absorption and addresses tunability challenges by utilizing a periodic sub-wavelength structure-based unit cell. The novel design comprises a concentric triangular strip within a central hollow of a square patch, with four hollow cylindrical spaces at the patch corners, each containing four small square pillars. The design comprises a metal–dielectric–metal architecture, with silver as the top patch and the ground metal layer separated by a thin magnesium fluoride dielectric layer. A temperature-controlled material vanadium dioxide layer is introduced below the upper metal layer to enhance the absorbance. Moreover, extensive parametric investigations have been conducted involving the manipulation of shape while keeping other dimensions constant. The goal is achieving perfect multiple absorptions within the 90–300 THz frequency range, ensuring impedance match and exhibiting plasmonic resonance characteristics. The study also investigates unit cell behavior regarding polarization and incident angle variations. Simulations are conducted using CST Microwave Studio Suite® with finite integration technology and validated with COMSOL Multiphysics® using the finite element method in the frequency domain. The simulated results reveal multiple absorption peaks in the terahertz range, averaging 98.32% with a maximum absorption of up to 99.99% and exhibiting high absorption coefficients at discrete resonance frequencies, suggesting promising applications in terahertz technology-related fields.

تقييم أداء هوائي المايكروسترب لتقليل إمتصاص الموجات الكهرومغناطيسية في األنسجة البشرية في نطاقات 5جي

The absorption of electromagnetic waves emitted by wireless devices in human tissues is quantified by the Specific Absorption Rate (SAR) measured for 1g or 10g of body tissues. The primary objective of this research is to identify an effective shield material that can minimize the impact and potential harm of electromagnetic waves on human tissues. The study involves the design of a single radiator Microstrip antenna operating at 28 GHz and the modelling of human tissue layers. SAR calculations for 1g of body tissues are performed based on the distance between the antenna and the head model. To evaluate the influence of antenna position on the head model, SAR calculations are conducted using two different approaches. In the first approach, the head model is positioned on the patch radiator side, while in the second approach, it is placed on the ground plane side. The aim is to determine which configuration yields lower SAR values. Furthermore, SAR calculations are reanalysed by incorporating shielding materials onto the Microstrip antenna. Three different absorbed materials are used as shields, and their impact on SAR reduction and radiation parameters of the Microstrip antenna are evaluated. The objective is to identify the shield material that achieves the highest SAR reduction while minimally affecting the radiation parameters of the antenna.

Electromagnetic interference shielding behavior of flexible PVA composite made using betel nut husk biocarbon and steel microwire in E, F, I, and J band spectrum

AbstractThis study investigates the electromagnetic interference (EMI) shielding behavior of a flexible polyvinyl alcohol (PVA) composite fabricated using betel nut husk biocarbon and steel microwire in the E, F, I, and J band spectrum. The incorporation of steel microwire into the PVA based composite is novel approach since it provides flexibility along with good mechanical strength. The fabrication process involves the solution casting method, and the composite is characterized according to American society of testing and materials (ASTM) standards. The research focuses on analyzing dielectric behavior, EMI shielding effectiveness, and mechanical properties. Results indicates that, the composite with 5 vol.% of biocarbon and 5 vol.% of micro metal wire, exhibits exceptional relative permittivity of 7.6, 6.9, 6.3, and 1.5 for E, F, I, and J frequency bands and same composition delivers exceptional electromagnetic shielding with total shielding values of 17.7 dB, 25.5 dB, 31.7 dB, and 38.6 dB for E, F, I, and J frequency bands. In mechanical characteristics, composite with 5 vol.% of biocarbon and 5 vol.% of micro metal wire, exhibits high tensile strength of 73 MPa with lower elongation percentage of 109.2% and shore‐D hardness of 40, respectively. Thus, the inclusion of betel nut husk biocarbon and steel microwire into the PVA matrix enhanced the overall EMI shielding properties along with mechanical properties. These flexible EMI shielding composites could be used in applications such as defense, telecommunication, drones, and electronic gadget making segments.Highlights Flexible polyvinyl alcohol (PVA) composite is made with steel microwire and betel nut husk biocarbon. Biocarbon is derived from betel nut husk for first time and used as EM wave absorber. Composites were made via simple solution casting method for high flexibility index. Composite contains 5 vol.% biocarbon and 5 vol.% micro metal wire, shows high relative permittivity 7.6 for E frequency bands. The composites have high tensile strength of 73 MPa with a low elongation percentage of 109.2% and a shore‐D hardness of 40.

Multifunctional bacterial cellulose‑derived carbon hybrid aerogel for ultrabroad microwave absorption and thermal insulation

Carbon aerogel has gained intense attention as one of the most promising microwave absorption materials. It can overcome severe electromagnetic pollution, thanks to its 3D macroscopic structure and superb conductive loss capacity. However, there is still a big challenge to endow multifunctionality to carbon aerogel while maintaining its good electromagnetic wave absorption (EWA) so as to adapt wide practical application. Herein, a novel carbon-based aerogel consisting of Cu and TiO2 nanoparticles dispersed on carbon nanofiber framework was derived from carbonized bacterial cellulose (CBC) decorated with its mother bacteria via freeze-drying, in situ growth and carbonization strategies. The synthesized carbon-based CBC/Cu/TiO2 aerogel achieved an excellent EWA performance with a broad effective absorption bandwidth (EAB) of 8.32 GHz. It is attributed to the synergistic loss mechanism from multiple scattering, conductive network loss, interfacial polarization loss and dipolar polarization relaxation. Meanwhile, the obtained aerogel also shows an excellent thermal insulation with a 3-mm-thick sample generating a temperature gradient of over 42 °C at 85 °C and a maximum radar cross-section (RCS) reduction of 23.88 dB m2 owing to the cellular structure and synergistic effects of multi-components. Therefore, this study proposes a feasible design approach for creating lightweight, effective, and multifunctional CBC-based EWA materials, which offer a new platform to develop ultrabroad electromagnetic wave absorber under the guidance of RCS simulation.

Microwave absorption parameters over 2–18 GHz frequency range for the MXene composite – Ti3C2Tx @MnCo2O4

The great potential for electromagnetic wave (EMW) absorption is revealed in two-dimensional (2D) Ti3C2Tx (MXene) thin sheets that have numerous surface flaws and an extensive spectrum of functional groups. In this study, Ti3AlC2 (MAX Phase) is etched, and then ultrasonic exfoliation is used to create 2D ultrathin Ti3C2Tx nanosheets; a type of MXene. The MnCo2O4 spherical particles were grown on the layered structure of Ti3C2Tx via a one-pot hydrothermal process. The synthesized Ti3C2Tx/MnCo2O4 composite provides superior bulk-to-surface and interfacial charge transfer capabilities due to their short charge transfer distance and extensive interface contact area to the EMW. This article thoroughly evaluates the loss impact in Ti3C2Tx/MnCo2O4 absorbers as -44.4dB of reflection loss at 16.04GHz with a thickness of 5.114mm for the first time, which is essential for fabricating an effective microwave absorber.

A Nanoconfinement Strategy to Construct Co@CNTs for Lightweight and Ultra-Broadband Microwave Absorption.

The construction of stable and efficient nanocomposites with low addition and light weight has always been the goal pursued in the field of electromagnetic wave (EMW) absorption. In this study, the Co@CNTs nanocomposites with Co nanoparticles (13nm) nanoconfined in the carbon nanotube (CNT) are successfully synthesized by a simple hydrothermal method and phenolic assisted pyrolysis method. The degree of graphitization of CNTs and the microstructure of Co nanoparticles can be effectively regulated by controlling the calcination temperature. The sample calcined at 700°C can obtain excellent absorption performance at a low filling capacity of 10 wt.%: the minimum reflection loss (RL) is -41.2dB and the effective absorption bandwidth (EAB) reaches a maximum width of 14.2GHz. When the sample thickness is only 2.2mm, the EAB of <-20dB reaches 8.3GHz, which is the maximum EAB of most current Co-based absorbers. In particular, the polarization and ferromagnetic coupling behaviors are elucidated in depth with the aid of electromagnetic field simulations using the High-Frequency Structure Simulator (HFSS). This work provides a new nanoconfinement strategy for constructing the Co@CNTs nanocomposites as lightweight and ultra-broadband absorbing materials for EMW protection and EMW pollution control.

Electromagnetic wave absorption performance of porous geopolymer: Dual effects of fly ash on alkali activation and microwave dissipation

The simultaneous occurrence of aggregation reactions in fly ash (FA) facilitates the uniform dispersion of internal ferrite into the geopolymer. Considering the excellent impedance matching and multiple reflection effects of foam concrete, this paper develops a ‘zero-absorber’ foam geopolymer-based electromagnetic absorbing material. The effects of different densities (400, 600, 800, 1000, 1200 kg/m3) and FA contents (40 %, 50 %, 60 %, 70 %, 80 %) on the electromagnetic absorption performance of foam geopolymer are investigated, respectively. Combined with the iron element distribution and 3D pore structure by SEM and X-CT analysis, the dissipation mechanism of electromagnetic energy by FA and pore structure in foam geopolymer are further explored. Experimental results show that FA can uniformly disperse inherent ferric ions from the matrix into the geopolymer during the polymerization reaction, leading to excellent magnetic losses through magnetic moment orientation adjustment and intermolecular friction interactions without adding external absorber. Additionally, the uniformly dispersed porous structure consumes incident electromagnetic energy through reflection, scattering, coherent attenuation, and interference resonance loss effects. It shows multi-scale electromagnetic absorption effects in the ‘zero-absorber’ foam geopolymer-based electromagnetic absorbing material, including pore structure multiple reflections (millimeter scale), inter-pore wall interference resonance (micrometer scale), and ferric ion magnetic loss (nanometer scale). For the foam geopolymer with 1000 kg/m3 density and 50 % FA, it achieves the optimal electromagnetic absorbing performance with the minimum reflection loss (RL) of −34.9 dB and the effective absorption bandwidth of 14.1 GHz (RL below −10 dB) in 2–18 GHz range.

Broadband asymmetric absorption-transmission and double-band rasorber of electromagnetic waves based on superconductor ceramics metastructures-photonic crystals

In this paper, a kind of superconductor ceramics metastructure-photonic crystals (SCMPC) is proposed to investigate the absorption and transmission properties of electromagnetic waves (EW) by combining a metastructure with multiple degrees of freedom regulation and strong energy localization characteristics of photonic crystals. Firstly, for the periodically aligned SCMPC, EW mainly realizes absorption in forward propagation and transmission in backward case. The relative bandwidth (RB) for both forward absorptivity and backward transmittance greater than 0.9 is 2.7 %, and the operating bandwidth (OB) is 696 ∼ 715 terahertz (THz), which is an asymmetric absorption-transmission (AAT) characteristics. Importantly, the periodically aligned SCMPC can realize the double-band rasorber phenomenon, and the forward EW exhibits an absorption-transmission-absorption phenomenon with OBs of 644.2 ∼ 671.1 THz, 700.9 ∼ 742.1 THz, and 766.8 ∼ 784.2 THz. RBs with absorption and transmissivity greater than 0.8 are 4.1 %, 5.7 %, and 2.2 %, respectively, and the backward EW one is mainly transmitted. To optimize AAT, a quasi-periodic Octonacci sequence-aligned SCMPC is introduced. The results show that the maximum OB of forward absorption and backward transmission is 428.3 ∼ 670.5 THz and RB is 44.1 %, achieving favorable broadband AAT. In addition, the effects of temperatures, dielectric thicknesses, and stacking numbers on AAT are also investigated in detail. In conclusion, AAT has promising applications in unidirectional optical transmission, photodiodes, optical isolators, etc.

Multi-interface engineering design of nitrogen-doped bamboo-based carbon/Fe/Fe3C composite electromagnetic wave absorber based on honeycomb-ant nest-like structure

The integration and development of artificial intelligence (AI) and 5G communication technology have brought tremendous changes to human society. How to create a green electromagnetic environment has attracted people's attention. Rich heterostructure design based on interface engineering is considered an effective means of obtaining efficient electromagnetic wave absorbers. In this work, we have achieved innovative design of nitrogen doped carbon/Fe/Fe3C multi-interface heterostructures. The delignification modification of bamboo enriches the cellular pore channels, effectively regulates the loading of Fe3+and the diffusion binding of pyrrole molecules and promotes the deep construction of multi-layer heterogeneous interfaces. Further in-situ pyrolysis resulted in the formation of abundant honeycomb ant nest like structural pores and nitrogen doped multiphase heterostructure interfaces. Provided the best multi-component loss mechanism and impedance matching for the material, improving the overall dielectric and interface polarization effects of the material. Therefore, the obtained absorbent exhibits satisfactory electromagnetic wave absorption performance at a low load of 20 %, with an effective absorption bandwidth of 6.5 GHz (1.85 mm). This work provides new ideas for the high-value utilization of biomass in nature, optimization and innovative design of multi-level pore structures for microwave absorbers.

Enhancing Defect-Induced Dipole Polarization Strategy of SiC@MoO3 Nanocomposite Towards Electromagnetic Wave Absorption

HighlightsOxygen-vacancy-rich SiC@MoO3 nanocomposite with strong reflection loss (− 50.49 dB at 1.27 mm thickness) and broadband absorption band (8.72 GHz at 2.68 mm thickness) were constructed via in situ etching strategy.The presence of oxygen vacancy leads to an increased conductive loss and defect-induced dipole polarization, which plays significant role in attenuating the incident electromagnetic wave.

Mechanically strong SiC aerogels with broadband electromagnetic wave absorption enabled by hollow skeleton and interface engineering

SiC aerogels have great potential as thermal insulation materials and wave absorbers owing to high porosity and excellent dielectric properties. Recently, many SiC based electromagnetic wave absorbers with excellent performance have been developed. However, the coordination of thermal insulation, mechanics and electromagnetic wave absorption remains a challenge. Reasonable skeleton design and interface engineering are effective methods to overcoming this challenge. Herein, we report a mechanically strong SiC aerogel with hollow SiC microtube skeletons and SiC-SiO2 heterogeneous structures through engineering its microstructure by a simple continuous sintering-etching-annealing process. Accordingly, the aerogel exhibits excellent mechanical properties with a maximum compressive stress of 2.86 MPa. In addition, the aerogel shows an ultra-low thermal conductivity of 0.028 W/(m·K). More importantly, the aerogel exhibits a wide-band absorption band of 6.7 GHz at a matching thickness of 3.3 mm. Therefore, the findings of this study not only provide a simple method for the microstructure regulation of SiC aerogels but also provide a new technique to enhance electromagnetic wave absorption by using heterogeneous interface engineering.

Rational design of ternary heterostructures 3D Flower- like CoS/Fe3O4@PPy for efficient electromagnetic wave absorption

The rational design of heterostructures with well-defined chemical composition and spatial configuration stands as a key approach in achieving exceptional performance in electromagnetic wave absorption. This innovative work investigated the electromagnetic wave absorption properties of flower-like CoS/Fe3O4@PPy composites synthesized by hydrothermal method and in situ polymerization. A comprehensive investigation was conducted into the phase composition, morphology, and absorption properties. Flower-like CoS/Fe3O4@PPy composite demonstrates remarkable microwave reflection loss of −58.4 dB and effective absorption bandwidth of 5.55 GHz in thickness of 3.1 mm. The superior performances are attributed to the synergistic interplay of interfacial polarization, dielectric loss, magnetic loss, and optimized impedance matching. Furthermore, sufficient decrease in radar cross-section value was observed for the optimal sample with reduction of 41.23 dBm². These results highlight the considerable potential of flower-like CoS/Fe3O4@PPy composites in addressing electromagnetic pollution and stealth applications.

Recent Progress of Iron-Based Magnetic Absorbers and Its Applications in Elastomers: A Review.

As a result of continuing scientific and technological progress, electromagnetic waves have become increasingly pervasive across a variety of domains, particularly within the microwave frequency range. These waves have found extensive applications in wireless communications, high-frequency electronic circuits, and several related fields. As a result, absorptive materials have become indispensable for dual-use applications across both the military and civilian domains because of their exceptional electromagnetic wave absorption properties. This paper, beginning with the operating mechanisms of absorptive materials, aims to provide an overview of the strategies that have been used to enhance the absorption performance of iron-based magnetic absorbers (IBMAs) and discuss the current research status of absorptive material components. The fabrication of a ferromagnetic absorber in terms of morphology, heterointerface coupling, and macrostructural enhancements and the effect of powder characteristics on their electromagnetic properties are discussed. Additionally, the application of IBMAs in elastomers is summarized. Finally, this paper summarizes the limitations of existing ferromagnetic absorber materials and offers a perspective on their potential future developments. The objective of the ongoing research is to fabricate absorptive components that have thin profiles, lightweight construction, wide absorption frequency ranges, and strong absorption capabilities.

FeSiBCuNbZr amorphous composites decorated with SiO2 and TiO2(B) (bronze phase TiO2) for efficient electromagnetic wave absorption

The application of Fe-based amorphous microspheres in high-performance electromagnetic wave absorbing materials is significantly limited by a single loss mechanism. Utilizing interfacial engineering and magnetic-dielectric synergistic effect is a viable approach to enhance microwave absorption. In this work, FeSiBCuNbZr amorphous microspheres were synthesized using single copper roller melt-spinning method and ball mill method. The finding reveals that the incorporation of SiO2 and TiO2(B) (bronze phase TiO2) shells notably enhances polarization loss and conductive loss. FeSiBCuNbZr@SiO2@TiO2(B) amorphous composites exhibited a minimum reflection loss value of −64.89 dB at a thickness of 2.17 mm and an effective absorption bandwidth (EAB) of 8.08 GHz covering 9–18 GHz at a thickness of 1.9 mm. The exceptional wave absorption performance is ascribed to the combined effect of magnetic loss in the FeSiBCuNbZr amorphous core and dielectric loss from the double-shell structure, while maintaining favorable impedance matching. This work provides a new core–shell FeSiBCuNbZr amorphous composites for efficient electromagnetic wave absorption.