Attenuation Of Electromagnetic Waves Research Articles

Imaging of permeability defect distribution by electromagnetic tomography with hybrid L1 norm and nuclear norm penalty terms

Electromagnetic tomography (EMT), with the advantages of being non-contact, non-invasiveness, low cost, simple structure, and fast imaging speed, is a multi-functional tomography technique based on boundary measurement voltages to image the conductivity distribution within the sensing field. EMT is widely used in industrial and biomedical fields. Currently, there are few studies on the application of EMT in magnetic permeability materials, which makes it difficult to obtain high-quality reconstructed images due to its own properties that lead to obvious attenuation of electromagnetic waves during propagation, as well as the ill-posed and ill-conditioned characteristics of EMT. In this paper, a multi-feature objective function integrating L2 norm regularization, L1 norm regularization, and low-rank norm regularization is proposed to solve the challenge of magnetic permeability material imaging. This approach emphasizes the smoothness and sparsity. The split Bregman algorithm is introduced to efficiently solve the proposed objective function by decomposing the complex optimization problem into several simple sub-task iterative schemes. In addition, a nine-coil planar array electromagnetic sensor was developed and a flexible modular EMT system was constructed. We use correlation coefficient and error coefficient as indicators to evaluate the performance of the proposed image reconstruction algorithm. The effectiveness of the proposed method in improving the reconstruction accuracy and robustness is verified through numerical simulations and experiments.

Construction of cobalt zinc metal-organic frameworks derived Co/CoO/C composites toward broadband and high-efficiency electromagnetic wave absorption

The fabrication of novel carbon-based electromagnetic wave (EMW) absorbers with broad absorption bandwidth, strong absorption strength, low filler loading ratio and thin matching thickness remains a challenging task. Metal-organic frameworks (MOFs) are widely recognized as ideal self-sacrificial templates for the construction of carbon-based EMW absorbers. In this work, bimetallic CoZn-MOFs derived Co/CoO/C composites were prepared by combining magnetic stirring with subsequent pyrolysis treatment. The results showed that the morphology of carbon skeletons evolved from an irregular agglomerate to a uniform hexagonal star shape and then to an agglomerate again by reducing the molar ratio of Co2+ to Zn2+. Remarkably, excellent EMW absorption capacity in the Ku-band was achieved through carefully regulating the molar ratio of Co2+ to Zn2+. When the filling ratio was 20wt.%, the prepared Co/CoO/C composite exhibited the best EMW absorption performance with the minimum reflection loss of -64 dB at a thickness of 1.79mm and the maximum effective absorption bandwidth of 6GHz at a thickness of 2.14mm. Furthermore, the radar cross section in the far-field was simulated by computer simulation technique. In addition, the possible EMW attenuation mechanism was proposed. Therefore, the results of this paper could be helpful for developing carbon-based magnetic composites derived from MOFs as broadband and high-efficiency EMW absorbers.

Interfacical polarization dominant rGO aerogel decorated with molybdenum sulfide towards lightweight and high-performance electromagnetic wave absorber

Lightweight reduced graphene oxide aerogel (rGO) has obtained enormous attention as microwave absorber due to anisotropic characteristics in their structure and electromagnetic parameters. However, the controllable preparation of reduced graphene oxide (rGO) aerogels with tailored multidimensional structure with broadened effective absorption bandwidth is a thorny difficulty. In this paper, rGO aerogel decorated with molybdenum sulfide (rGO/MoS2) with three-dimensional (3D) layered porous structure were synthesized by a two-step hydrothermal method. The unique three-dimensional layered porous structure of graphene aerogel not only effectively avoids the stacking of graphene flake layers, but also provides space for the loading of MoS2 nanosheets. The introduction of MoS2 nanosheets compensates for the imbalance of impedance matching caused by graphene due to the excessive conductivity, and the folded MoS2 nanosheets are uniformly loaded on the graphene lamellae, which is conducive to generate multiple reflections and scattering of electromagnetic waves. Besides, the construction of heterogeneous interfaces strengthens the interfacial polarizability of the composites. As a result, excellent electromagnetic wave attenuation properties were obtained for rGO/MoS2, and the effective absorption bandwidth (EAB) reached 6.56 GHz at 2.1 mm. In addition, the radar cross section (RCS) simulation results further demonstrate the dissipation capability of the composite in practical application scenarios. This paper provides a new idea for the design of lightweight EM wave absorbing materials with broad absorption bandwidth.

Prediction of Broadband and Highly-Efficient Electromagnetic Wave-Absorbing SiC@SiO2 Nanowire Aerogel by Genetic Algorithm.

Searching for lightweight and high-temperature stable electromagnetic wave-absorbing materials with broad absorbing bandwidth and high efficiency is of significance for applications in daily life and industry. Optimizing the dielectric properties of SiC nanowire aerogel by both compositional and structural designs is an efficient way to obtain simultaneous efficient wave-dissipation ability and good impendence matching and thus the desired properties. However, due to the complex effects of dielectric parameters on the wave-absorbing properties, rational design of high-performance electromagnetic wave-absorbing materials remains challenging. Herein, we propose a genetic algorithm-based approach to predict broadband and highly efficient electromagnetic wave-absorbing materials in a SiC@SiO2 nanowire aerogel-based system. The obtained SiC@SiO2 nanowire aerogels exhibit a gradient multilayered structure with a low dielectric outer layer, a medium layer with alternatively distributed electromagnetic wave transparent and attenuation layers, and an inner high attenuation layer, giving it a broadband electromagnetic wave-absorbing performance covering almost all the 2-18 GHz bandwidth and simultaneous high efficiency. The results show that the genetic algorithm-based approach is efficient in predicting high-performance electromagnetic wave-absorbing ceramic aerogels.

Carbon Nanotube Grown from Cobalt Supported on Biomass-Derived Carbon as Nanocomposite for the Attenuation of Electromagnetic Waves

Carbon Nanotube Grown from Cobalt Supported on Biomass-Derived Carbon as Nanocomposite for the Attenuation of Electromagnetic Waves

One-step pyrolysis derived Fe and heteroatom co-doped biochar composites for efficient microwave absorption

Electromagnetic (EM) pollution frequently disrupts the regular operation of sophisticated electrical devices, necessitating the urgent development of lightweight EM wave absorbers that possess powerful absorption capability. Herein, we report a simple method for the preparation of Fe and heteroatom co-doped biochar composites (FeX-BC, where X = N, S) by directly carbonizing the precursors of anhydrous FeCl3, cherry kernel powder, and heteroatom dopants (melamine or Na2S2O3·5H2O). By adding different amounts of dopants during the synthesis of the precursors, it is possible to adjust the heteroatom content of the FeX-BC samples with precision. It is worth mentioning that the FeN0.1-BC composite delivers the best EM wave absorption performance with an effective absorption bandwidth of 4.8 GHz and a minimal reflection loss of −63.2 dB. Furthermore, the significant attenuation of EM wave can be attributed to the synergistic interplay of magnetic loss, dielectric loss and the enhanced impedance matching. This study introduces a simple methodology for the fabrication of EM wave absorbers, a significant contribution to the synthesis, advancement, and functional applications of biomass-derived materials.

Constructing multiple hetero-interfaces with rGO supported globular shaped PEDOT/Fe3O4 toward high-efficiency electromagnetic wave attenuation

Constructing multiple hetero-interfaces with rGO supported globular shaped PEDOT/Fe3O4 toward high-efficiency electromagnetic wave attenuation

Multilayer porous poly (vinylidene fluoride)/MXene/cobalt ferrite composites with ternary gradients for electromagnetic wave absorption

A composite material with a high potential for absorbing electromagnetic waves (EMW) was obtained by selecting poly (vinylidene fluoride) (PVDF) as the matrix, MXene as the conductive filler, and cobalt ferrite (CoFe2O4) as the magnetic filler. A layer-by-layer assembly strategy involved hot pressing and sequential blade coating, followed by vapor-induced phase separation, was used to implement the preparation of PVDF/MXene/CoFe2O4 (PMC) composites. The process facilitates the formation of a well-organized multilayer porous framework, providing a gradient of positive conductivity, negative magnetism, and porosity within the composites. Incorporating distinct multilayer, porous, and gradient structures into a single composite led to exceptional impedance matching (Z), with an area percentage of up to 8.4 % in the optimal range of 0.8 to 1.2. Furthermore, the multiple interfaces formed by the various components, multilayer structure, and porous configuration significantly enhanced the EMW attenuation capability, with the attenuation constant reaching as high as 274. Consequently, the PMC composite demonstrated outstanding performance with a minimal reflection loss (RLmin) of −56.5 dB, a specific RLmin of 23.5 dB/mm, and the broadest effective absorption bandwidth of 3.2 GHz. The combination of the competitive EMW absorption capability, low density, flexibility, adequate tensile strength, and amphiphilic Janus surface may significantly broaden the application scenarios of PMC composites.

Synergistically magnetic and dielectric properties of two dimensional Fe3Al@PPy lamellae exhibiting broadband and strong electromagnetic wave absorption

Addressing the issue of low impedance characteristics is essential to improve the electromagnetic wave absorption performance of magnetic materials. Herein, two dimensional Fe3Al@polypyrrole (PPy) lamellae with synergistic magnetic and dielectric properties are fabricated by a mechanical alloying, ordering transformation and polymerization process, which exhibits excellent electromagnetic wave absorption performance. By carefully controlling the thickness of the PPy shell, the optimized Fe3Al@PPy lamellae show a minimum reflection loss of −45.6 dB and an effective absorption bandwidth of 9.1 GHz at a thickness of only 1.5 mm. The conformal growth of Fe3Al@PPy lamellae can induce strong interfacial polarization, dipole polarization, multiple scattering effect and magnetic loss behaviors for the attenuation of electromagnetic waves. This study demonstrates a facile strategy for the development of efficient Fe3Al@PPy composite absorbents showing great potential for practical applications.

Lightweight composites derived from carbonized taro stems for microwave energy attenuation and thermal energy storage

A novel strategy has been developed for preparing porous carbon materials derived from taro stems, aimed at enhancing electromagnetic wave (EMW) attenuation and thermal energy storage. The materials were synthesized through the carbonization of taro stems to form a porous carbon structure, subsequently enhanced with polyethylene glycol (PEG) containing carbon nanotubes (CNTs) and nickel (Ni) nanoparticles. By adjusting the carbonization temperature and the loading of CNTs and Ni, the resulting carbon materials exhibited exceptional EMW attenuation performance. Specifically, the PC-800 sample demonstrated a remarkable minimum reflection loss of −61.4 dB across the frequency range of 8.2–11 GHz, with a low density of 0.054 g/cm³. The PC-1200 sample exhibited EMI SE values of 23.6 dB axially and 21.5 dB radially in the X-band, with an ultra-low density of 0.033 g/cm³. Further enhancements were observed in the PC/CNT2 and PC/CNT2-Ni15 composites, achieving EMI SE values of 26.3 dB and 26.8 dB, respectively. Additionally, these composites exhibited effective thermal energy storage and release, as confirmed by heating experiments. This study not only introduces a method for creating absorption-dominated biomass electromagnetic shielding materials but also provides a dual-functional solution for enhancing the performance of electronic devices.

High-entropy TiVNbMoC3Tx MXene hybrid with balanced dielectric-magnetic loss for high-efficient electromagnetic wave absorption with environmental stability

With the advent of the 5G era, there is a growing demand for electromagnetic wave (EMW) absorbers that offer both efficient absorption and improved environmental stability. Transition metal carbides/carbonitrides (MXene), with their atomic-layered structures and high electrical conductivity, offer substantial potential for crafting efficient electromagnetic functional materials. Yet, enhancing the antioxidant capabilities and addressing the poor loss mechanisms of traditional MXene absorbers remain challenging tasks. In this context, a TiVNbMoC3Tx high-entropy MXene (HE-MXene) and its magnetic hybrids were synthesized for the first time. The unique multicomponent structure of high-entropy MXene reduces grain boundary formation, thereby slowing the progression of oxidation reactions. The incorporation of magnetic nanoparticles induces interface polarization loss or strong magnetic coupling, thereby enhancing EMW attenuation. These magnetic HE-MXene hybrids demonstrated a minimum reflection loss of −57.59 dB at a matching thickness of 1.46 mm and an effective absorption bandwidth (EAB) of 4.72 GHz at a thickness of 1.53 mm. Furthermore, the magnetic hybrids also exhibited outstanding oxidation and electrochemical corrosion resistance. This research provides valuable theoretical insights for the development of electromagnetic composites within high entropy (HE) systems, showcasing significant potential for long-term applications.

Phase Engineering in a Twin‐Phase β/γ‐MoCx Lightweight Nanoflower with Matched Fermi Level for Enhancing Electron Transport Across the Polarized Interfaces in Electromagnetic Wave Attenuation

AbstractThe phase engineering of the polarization interface is of great significance in modifying dielectric loss in electromagnetic wave (EMW) attenuation process, but hard to conduct in a complex hybrid system. Herein, a twin‐phase of β/γ‐MoCx@CN with matched Fermi level and closed work function properties in lightweight MoCx nanoflower is constructed, facilitating electron transport withdraw enhanced conductivity and polarization. Moreover, the EMW multiple dissipations among the β/γ‐MoCx@CN polarization interface is promoted, displaying better matched impedance. It delivered a remarkable minimum reflection loss (RLmin) of −74.2 dB at the thickness of 1.5 mm, which far beyond the single phased β‐MoCx@CN, γ‐MoCx@CN and reported MoCx‐based EMW absorbers. The radar cross‐section (RCS) map of β/γ‐MoCx@CN is simulated, showing a brilliant maximum reduction value of 13.6 dB m2 at the theta angle of 30°. This work presented an excellent sample of atomic‐level manipulation of interfacial polarization in dielectric MoCx EMW absorption materials.

Assessing the electromagnetic shielding effectiveness of coconut coir composites with varying iron particle concentrations

This study investigates the electromagnetic shielding effectiveness of Coconut Coir-based Porous Carbon (CCPC) composites with varying iron (Fe) particle concentrations, specifically focusing on four different weight ratios of CCPC/Fe-80, CCPC/Fe-60, CCPC/Fe-40, and CCPC/Fe-20. The novelty of this work lies in the use of sustainable coconut coir as a base material, emphasizing its eco-friendly and cost-effective attributes for Electromagnetic interference (EMI) shielding applications. The significance of varying iron particle concentrations is highlighted to optimize electromagnetic shielding effectiveness. Comprehensive analyses were conducted on these composites. X-Ray Diffraction (XRD) analysis confirmed the presence of crystalline Fe particles and amorphous carbon, with crystalline sizes determined via Williamson-Hall (W-H) plot, Scherrer Equation, and Strain Size Plot (SSP) ranging from 17.33 nm to 18.01 nm for the former. Raman spectroscopy revealed distinctive D and G bands, with intensity ratios indicating a slight increase in structural disorder with higher Fe content. UV-Visualization spectroscopy demonstrated distinct absorption peaks, with higher Fe content resulting in more pronounced absorbance and lower band gap energies. Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) analyses provided detailed insights into the material's microstructure and elemental composition, confirming the successful integration of Fe particles within the porous carbon matrix. Vector Network Analyzer (VNA) testing measured the reflection loss (RL), showing values in the range of −26.4 dB to −20.2 dB, for 2 mm thick samples, corresponding to electromagnetic wave attenuation of over 99%. These results underscore the potential of CCPC/Fe composites, particularly in applications requiring effective Electromagnetic (EM) wave attenuation. This research offers a sustainable and cost-effective solution, contributing significantly to the field of materials science by enhancing electromagnetic compatibility in various technological applications.

Progressive hollow engineering induced raspberry-like magnetoelectric microspheres via synergistic etching-assembly strategy toward boosted microwave attenuation

Optimizing the electromagnetic (EM) properties of composites through elaborate tailoring of their microstructures has become an attractive research branch, but determining the correlations between morphology, composition, and performance remains challenging. Herein, a novel progressive hollow engineering strategy is proposed for the construction of hollow CuFe Prussian blue analog (CuFePBA, CF) precursors with asymptotic variations of cavities and PBA units based on a synergistic etching-assembly approach, subsequently combined with a polydopamine (PDA) coating and carbothermal process to acquire raspberry-like hollow Cu/Fe/Fe3C@NC (CFC) composites. The proposed approach addresses the drawbacks caused by organic ligand depletion or corrosive agent usage. We then present a systematic investigation of the mechanism by which the progressive hollow engineering-induced concurrent evolution of hollow cavities, phases, defects, and inhomogeneous interfaces contributes to the improvement of the dielectric properties of the CFC samples. An optimal reflection loss (RLmin) of − 65.17 dB at 3.29 mm was realized for the CFC-2 sample and the CFC-3 sample achieved an effective absorption bandwidth (EAB) of 4.4 GHz at an ultra-thin thickness of 1.29 mm. This work reveals the synergistic effects of compositional, interfacial, and defect variations on the EM wave attenuation properties of the composites, and will provide new design inspiration for novel absorbers with modulatable hollow architectures.

Engineering of N doped carbon@FeCo alloy hollow spheres: Remarkable mid-frequency electromagnetic wave absorption performance exhibited by unique porous and wrinkled surface structure

The modulation of the shape and design of microstructures plays a crucial role in enhancing the efficient absorption of electromagnetic waves in absorbers. The electromagnetic parameters and scattering effects of these materials are directly influenced by their morphological characteristics. In this study, polystyrene microspheres were used as templates for a two-step in-situ growth process: Initially, Fe₃O₄ was coated onto the surfaces of these microspheres, followed by the in-situ growth of Fe-Co Prussian blue analogs. The rational design of electrical parameters during the conversion process was calculated and analyzed using Density Functional Theory. The precursor was calcined at various temperatures to generate a unique porous wrinkled surface hollow nanostructure. This nanostructure not only facilitates multiple reflections and scattering of incident electromagnetic waves but also promotes the occurrence of multiple interface polarizations. Doping with nitrogen and oxygen elements introduced abundant dipole polarization, thereby enhancing the electromagnetic wave attenuation capability of the composite material. The Fe3O4@PBA composite material synthesized at 600°C achieved a minimum reflection loss of −57.01 dB and a maximum effective absorption bandwidth of 4.58 GHz (7.52–12.1 GHz) at a thickness of 4 mm, covering nearly the entire X-band. This method provides a means to enhance magnetic loss by temperature adjustment to control the magnetic components in composite materials, providing a systematic approach to designing the microstructure of materials used for absorbing electromagnetic waves.

Boosting the Intelligent Development of Electromagnetic Shielding Polymer Composites by Expert Knowledge

AbstractAn intelligent process for developing electromagnetic interference (EMI) shielding composites is imperative to eliminate the escalating pollution of electromagnetic waves (EMWs). Meanwhile, integrating porous and/or layered structures with polymers is demonstrated as an effective approach. Herein, expert knowledge serves as the guidance of the Simulation‐First Strategy in designing shielding structures that incorporate MXene bubble wrap‐like aerogels (MBa‐bA), characterized by distinct bubble diameters a and densities b. The simulated EMI shielding efficiency (EMI SE) of corresponding MBa‐bA/polyethylene glycol (MBa‐bAP) composites is predicted through the finite element analysis (FEA) simulation. Subsequently, the MBa‐bAP composites are fabricated by template methods and exhibit an outstanding EMI SE of up to 83.1 dB and an ultrahigh SE of absorption (SEA) of 75.1 dB in X band at a = 10 µm and b = 0.50, perfectly aligning with the simulation outcomes. Combined with macro‐scale FEA simulation and experimental evidence, the pronounced EMWs attenuation effect, heat storage/release, and mechanical performances of MBa‐bAP composites are unequivocally substantiated. Based on these, this work proves the feasibility of the intelligent development strategy and provides a research basis for developing advanced EMI shielding materials directed by expert knowledge.

Achieving efficient electromagnetic absorption in multifunctional carbon nanotube aerogels by manipulating radialized network structure

The rapid advancements in communication technology have greatly propelled the widespread applications of artificial intelligence (AI). While AI technology facilitates society, it also brings the unavoidable electromagnetic hazards and the issue of disposal of electronic plastic wastes. So, utilizing electronic plastic wastes to constructing carbon-based electromagnetic wave (EMW) absorption materials, are highly promising. However, how to use CNTs from plastic wastes to build good EMW absorption performance aerogels is a critical challenge. In this work, highly porous and well-interconnected network aerogels constructed by radialized CNT arrays are rationally designed under the guidance of grave-to-cradle strategy, exhibiting altered impedance matching and multiple EMW attenuation methods. Theoretical calculations suggest that a well-designed heterojunction interface structure can enhance the conductivity and interface polarization of CNTAs. The CNT aerogels (CNTAs) realize broad absorption bandwidth covering 8.48 GHz with a minimum reflection loss of −59.5 dB. Moreover, the radialized arrays network of CNTAs also endows it with electromagnetic protection, thermal management, self-cleaning, and air purification functions. These inspiring achievements of multifunctional CNTA-2 provides new help for the safe and stable promotion of the AI era.

Multi-heterogeneous interfaces boost dielectric polarization in PBA-derived Co/MnO@NC ternary composites for electromagnetic wave absorption

The elaborate construction of multi-component composites has been deemed as a promising strategy to enhance dielectric polarization response capability in the preparation of highly efficient microwave absorbers. However, the rational design and integration of homogeneous composites with diverse components continues to pose a great challenge. Herein, we propose a straightforward self-assembly-carbonization strategy for fabricating Co/MnO@NC ternary composites derived from CoMn-Prussian Blue Analogous precursors, featuring enriched heterogeneous interfaces and balanced magneto-electric coupling synergy. The ternary composites effectively introduce diverse dissipation mechanisms, including interfacial polarization behavior originated from the constructed heterogeneous interfaces, dipole polarization relaxation triggered by atomic defects, and optimized magnetic loss ability from well-dispersed metallic Co species. Benefiting from these advantages, the Co/MnO@NC composites demonstrate superior electromagnetic wave absorption performances, with a minimum reflection loss value of −61.37 dB at the thickness of 3.5 mm and effective frequency absorption bandwidth of 6.32 GHz, covering the full Ku-band. Furthermore, power loss density and radar cross-section simulations validate that the Co/MnO@NC ternary composites possess exceptional microwave signal attenuation abilities, with a maximum radar cross-section reduction value of up to 27.98 dBm2 at 0°. Such outstanding absorption properties exceed those of most currently reported ternary composites and exhibit significant potential to replace conventional ferromagnetic-based absorbers. This work offers a straightforward strategy to fabricate ternary composites with excellent electromagnetic wave attenuation properties and sheds novel insights into the dissipation mechanisms.

Three-dimensional n-MoSe2/GOx (n= 1T, 1T' and 2H) microsphere: Phase-modulation strategy and microwave absorbing mechanism

MoSe2 was identified as a potential microwave absorber, whereas its practical application was predominantly affected by the ambiguous electromagnetic wave attenuation mechanism and dielectric properties. Here, we developed a novel phase assembly-modulating strategy to prepare n-MoSe2/GOx (n = 1T, 1T' and 2H) composites, wherein phase modulation of MoSe2 exerted a gainful effect on microwave absorption properties. The unique 1T′-MoSe2 phase was first explored in microwave absorption and composited with GOx to afford advanced conductivity loss and dielectric loss. The introduction of additional interface (2H/1T or 2H/1T') and abundant unsaturated defects promote multiple polarization, the semiconductor-metal mixed phase brought in a certain magnetic loss, optimizes the electron transfer ability and adjusts the impedance matching. Consequently, 1T′-MoSe2/GOx provides the minimum reflection loss (RLmin) of −52.08 dB and the effective absorption bandwidth (EAB, RL < -10 dB) of 5.3 GHz at 10 % filler content, which is approximately 9 times that of 2H–MoSe2/GOx and nearly 5 times that of 1T-MoSe2/GOx. This paper specifically explains the reasons for the phase modulation-induced magnetic losses and provides an effective phase modulation paradigm for developing advanced transition metal disulfide (such as MoS2, WS2 and WSe2) microwave absorbers.

Effects of the SmFeN content on the electromagnetic wave absorbing properties of sandwich-structured YSZ/SmFeN/YSZ composites

In this study, the thermal barrier material Yttria Stabilized Zirconia (YSZ) and the electromagnetic wave (EMW) absorbing agent samarium iron nitrogen (SmFeN) were used to prepare a YSZ/SmFeN/YSZ sandwich-structured composite. The YSZ/SmFeN interface was prepared perpendicular to the directions of EMWs. The EMW attenuation of the composites with different SmFeN contents and their mechanisms were studied using electromagnetic parameters, impedance matching, Cole–Cole circles, and minimum reflection loss (RLmin value). Dielectric loss was the dominant mechanism behind EMW attenuation for the composites. In addition, the dipole orientation of SmFeN and the presence of phase interface induced the dielectric loss. The mechanism of dipole orientation polarization was influenced by SmFeN content; the lesser the SmFeN content in the composite, the higher the ε′ (real part of dielectric coefficient). The frequency at which ε ′ peaked shifted decreased with increasing SmFeN content. Higher dielectric losses were observed in the frequency band of 4.0–8.0 GHz. The EMW absorption rate showed that the optimum EMW absorption effect was achieved when the thickness ratio of YSZ:SmFeN:YSZ was 1:4:1 and the thickness is 3.325 mm. The corresponding RLmin was −35.3 dB and effective absorption bandwidth was 9.5 GHz (8.3–17.9 GHz).