Microwave Absorption Performance Research Articles

Design and Optimization of Microwave‐Absorbing Structures With Carbonyl Iron Powder–Functionalized Continuous Carbon Fiber Grids Embedded in Continuous Glass Fiber‐Reinforced Composites

ABSTRACTIntroducing periodic structures into GFRP is a key approach to integrating structural and microwave‐absorbing functions. However, conventional metallic periodic structures often cause stress concentration problems. In this study, periodic CIP/CF grid structures were embedded into GFRP laminates, which were made from CIP‐modified continuous CF tapes. This design uses epoxy resin for integral molding of continuous GFs and CFs, which can effectively prevent interfacial stress concentration and maintain the excellent mechanical properties of GFRP laminates. Critical geometric parameters, including the CIP/CF grid bandwidth and GFRP layer thickness, were optimized using the genetic algorithm in MATLAB. The optimized structure was then modeled, and its microwave absorption performance was verified using HFSS software. Experimental results confirmed the HFSS simulation data, showing effective absorption in the 6.3–8.8 and 10.3–18 GHz frequency bands, with a peak absorption of −33.8 dB. Additionally, the microwave‐absorbing laminate with periodic CIP/CF grid retained the inherent high specific strength of GFRP and exhibited improved flexural strength, reaching 470 MPa (a 7% improvement over neat GFRP). The combined electromagnetic properties of GFRP, CF, and CIP, along with the synergistic effect of the CIP/CF grids, enabled the ultimate laminate to achieve broadband microwave absorption performance.

The evolution and degradation mechanisms of microstructure, mechanical and microwave absorption performance in RA SiC fibers

The evolution and degradation mechanisms of microstructure, mechanical and microwave absorption performance in RA SiC fibers

Enhancement of microwave absorption performance of MOF-derived NiCo2O4 by adding Ti3C2Tx MXene

Enhancement of microwave absorption performance of MOF-derived NiCo2O4 by adding Ti3C2Tx MXene

Alkalized chemical scissors form honeycomb MXene for enhanced microwave absorption performance

Alkalized chemical scissors form honeycomb MXene for enhanced microwave absorption performance

Preparation and microwave absorption performance study of high-entropy MAX phase (Ti1/4V1/4Zr1/4Nb1/4)2AlC

Preparation and microwave absorption performance study of high-entropy MAX phase (Ti1/4V1/4Zr1/4Nb1/4)2AlC

Facile synthesis of cross-linked network structure CoNiZnFe2O4@CNT composite with excellent microwave absorption performance

Facile synthesis of cross-linked network structure CoNiZnFe2O4@CNT composite with excellent microwave absorption performance

Introducing wave-transparent material SiO2 as a modification to optimize the microwave absorption performance of porous carbon composite MnFe2O4 ferrites

Introducing wave-transparent material SiO2 as a modification to optimize the microwave absorption performance of porous carbon composite MnFe2O4 ferrites

Core–Shell rGO‐BN Heterostructures Endowing Polybutadiene Composites with High Thermal Conductivity and Efficient Microwave Absorption

Abstract The continuous miniaturization and high integration of electronic devices have intensified heat dissipation and electromagnetic interference issues while also limiting the simultaneous application of thermal interface and microwave absorbing materials. Thus, developing interface materials with both high thermal conductivity and efficient microwave absorption has become crucial. Herein, a core–shell rGO‐BN heterostructure filler is reported with both high thermal conductivity and efficient microwave absorption performance, which is fabricated through the self‐assembly of polydopamine‐coated spherical boron nitride (BN) and graphene oxide (GO) and followed by thermal reduction. The rGO‐BN is used as thermally conductive/microwave absorption filler and blended with boron nitride nanosheet (BNNS) and polybutadiene (PB) to prepare rGO‐BN/BNNS/PB composites. When the mass fractions of rGO‐BN and BNNS are 45 and 13 wt.%, respectively, the rGO‐BN/BNNS/PB composites exhibit thermal conductivity of 5.94 W m−1 K−1, minimum reflection loss of −50.10 dB (3.9 mm, 8.42 GHz), and effective absorption bandwidth of 5.25 GHz (2.7 mm, 10.70–15.95 GHz), surpassing the current state of the art. This work provides fresh perspectives for overcoming the trade‐off between high thermal conductivity and excellent microwave absorption.

Excellent Microwave Absorption Properties in the C Band for the Nitrided Y2Fe12Co4Si/Paraffin Composites

The nitriding process was employed to optimize the low-frequency microwave absorption properties of Y2Fe12Co4Si/paraffin composites. The effects of nitriding temperature on the phase composition, static magnetic properties, electromagnetic parameters, and microwave absorption performance were systematically investigated. As the nitriding temperature increases, lattice expansion results in a significant increase in saturation magnetization and a higher ratio of in-plane to out-of-plane anisotropy fields. This, in turn, boosts the electromagnetic parameters of the composite material. With a further rise in temperature, an increased content of α-Fe is produced and the ratio of the in-plane to out-of-plane anisotropy field diminishes, leading to a decline in electromagnetic parameters. At 500 °C, these factors reach an optimum level, maximizing the composite’s electromagnetic parameters. The composite exhibited a minimum reflection loss (RLmin) of −55.9 dB at 5.58 GHz with a thickness of 2.46 mm. Moreover, at a thickness of 2.21 mm, the composite achieved a maximum effective absorption bandwidth (EABmax) of 2.95 GHz (5.05–8 GHz). Compared with other low-frequency-absorbing materials, the composite exhibited stronger absorption and a wider absorption bandwidth at a lower thickness in the C band.

Design of Multi‐Interface Hydrogenated Yolk–Shell C@TiO2 Microspheres With Enhanced Microwave Absorption Performances

ABSTRACTRational design on the microstructure and chemical composition is a feasible strategy to boost the performance of some conventional microwave absorbers. In this study, we designed and synthesized unique hydrogenated yolk–shell C@TiO2 composites (C@TiO2‐H2). The results indicate that the as‐prepared composite can effectively modify the matching degree of characteristic impedance and dielectric loss property by high complex permittivity carbon cores, crystal/disorder microstructure of TiO2 shells, and yolk–shell microstructure. The maximum reflection loss is −76.8 dB at 7.6 GHz with an absorber thickness of 3.0 mm. With an absorber thickness of 2.0 mm, the bandwidth over −10.0 dB is 4.5 GHz from 10.7 to 15.2 GHz. Notably, C@TiO2‐H2 outperformed TiO2, hydrogenated TiO2 (TiO2‐H2), carbon microspheres (Cm), as well as unhydrogenated yolk–shell C@TiO2 (C@TiO2‐N2) microspheres, where superior reflection loss and wide response bandwidth can be achieved simultaneously. Therefore, the yolk–shell C@TiO2‐H2 microspheres are expected to be promising candidates for microwave absorption applications.

Research on the Geometry Control and Microwave Absorption Performance of Auxetic Materials

There is great potential for the development of microwave-absorbing materials (MAMs) for structural regulation. Auxetic structures have excellent mechanical properties, which can be applied to multifunctional MAMs in various fields. Here, the microwave absorption performances of the auxetic structures were simulated using the High-Frequency Structure Simulator (HFSS), by regulating the structure, dielectric constant, layer number, and pore size. The simulation results show that increasing the dielectric constant, layer number, or decreasing pore size will lead to a decrease in the frequency of minimum reflection loss (RLmin). The main purpose of this study is to elucidate the influence of structure, dielectric constant, layer number, and pore size on the absorption performance of auxetic structures and obtain practical auxetic MAMs with a performance of RLmin < −30 dB and effective absorption bandwidth (EAB) > 3 GHz. Finally, practical auxetic MAMs between 8 and 18 GHz and MAMs optimized in dielectric constant were obtained, which were proven to have the advantages of lightweight characteristics, high absorption, and wide bandwidth. The four structures exhibit great RLmin values of −51.09, −55.52, −47.09, and −54.98 dB with wide EAB values of 3.25, 3, 4.75, and 4.5 GHz, demonstrating the strong electromagnetic wave absorption performance of auxetic structures. This work provides theoretical guidance for the study of auxetic structures in the field of microwave absorption and provides an effective approach for multi-disciplinary research on MAMs.

Design and Optimization of Gradient Foam Core Sandwich Structures With Superior Microwave Absorption Performance

ABSTRACTWith the increasing demand for omnidirectional wideband radar stealth performance in fifth‐generation fighter jets, foam sandwich structures used in aerospace must possess excellent microwave absorption (MA) capabilities. In this study, 20 types of rigid closed‐cell microwave‐absorbing composite foams were prepared using a microsphere foaming method, with short carbon fibers (SCF), multi‐walled carbon nanotubes (MWCNT), and carbonyl iron powder (CIP) as absorbing agents and epoxy resin (EP) as the matrix. The effects of absorbing agents' types and contents on the microwave absorption performance of the foams in the 2–18 GHz range were analyzed. Based on the experimental data, a data enhancement method was employed to expand the material database of foams. Subsequently, a multi‐objective optimization of gradient foam sandwich structures (GFSS) was conducted using a genetic algorithm. The effective absorption bandwidth (EAB) of the sandwich structures ranged from 13.9 to 16.0 GHz, the minimum reflection loss (RLmin) reached −94.4 dB, and the ratio of EAB to density (η) was 34.8–50.2 GHz g−1 cm3. Additionally, the gradient foam with a thickness of 20 mm exhibited an EAB of 16.0 GHz and an η value of 60.1 GHz g−1 cm3. The effectiveness of the optimization results was validated through experimental measurements. A finite element analysis (FEA) model was established to investigate the broadband MA mechanisms of the GFSS. Finally, the bending performance of the GFSS was evaluated by conducting three‐point bending tests. This study provides an effective approach for the design and fabrication of lightweight GFSS with broadband microwave absorption functionality.

Graphitization Optimization of Cobalt-Doped Porous Carbon Derived from Seaweed Sludge for Enhanced Microwave Absorption.

Utilizing biomass resources to develop carbon-based microwave-absorbing materials adheres to the principles of sustainable development. Nevertheless, the single loss mechanism of pure carbon materials is limited. Additionally, the carbonization of artificially synthesized polymers has poor environmental performance and involves complex processes. These issues restrict their performance and broader applicability. In this study, cobalt-doped seaweed sludge porous carbon (Co/SSPC) with different cobalt contents was synthesized via a simple grinding-carbonization treatment. The addition of cobalt can regulate the graphitization degree of porous carbon, achieving a suitable amorphous-to-crystalline carbon ratio of 2.05. This not only enhances magnetic loss but also modifies dielectric loss and optimizes impedance matching. The construction of synergistic magnetic and dielectric loss mechanisms enables Co/SSPC to exhibit excellent microwave absorption performance. Specifically, Co/SSPC achieved a minimum reflection loss (RLmin) of -66.91 dB at a thickness of 4.79 mm and an effective absorption bandwidth (EAB) of 5.09 GHz at a thickness of 1.6 mm. This study provides a practical approach for the functional application of natural polymer waste algal sludge and highlights its potential in the low-cost production of microwave absorbing materials.

Robust Single-Walled Carbon Nanotube-Coated Aramid Fibers with Tunable Conductivities for Broadband Radar Absorption in Honeycomb Structures.

Single-walled carbon nanotubes (SWNTs), renowned for their high strength and electromagnetic properties, provide a potential solution for next-generation honeycomb-structured radar-absorbing materials (HRAMs). However, the integration of SWNTs into HRAMs is hindered by challenges including poor dispersion, wash-off loss, and the absence of scalable, compatible fabrication methods. Herein, we address these challenges by synthesizing tunable conductive SWNT-coated aramid fibers (SWNT-AF) via a continuous dip-coating method and integrating them into aramid paper-based composites (APBC) to fabricate HRAMs. The SWNT-AF serve as both structural reinforcements and dielectric loss centers within APBC, avoiding direct dispersion of SWNTs into the pulp and thereby mitigating agglomeration and wash-off loss. The optimized APBC, reinforced with these tailored fibers, exhibit improved dielectric properties, resulting in enhanced microwave absorption performance. The fabricated HRAMs achieve an effective absorption bandwidth of 14.8 GHz (2.0-18.0 GHz) with an ultralow SWNT loading of 0.2 wt % and a thin thickness of only 30 mm, demonstrating a reflection loss of -47.78 dB. These results highlight the potential of SWNT-AF as lightweight, broadband radar-absorbing materials for stealth applications.

Construction biomass carbon@BaFe12O19 composites for excellent microwave absorption performance in mid-to-low frequency

Construction biomass carbon@BaFe12O19 composites for excellent microwave absorption performance in mid-to-low frequency

The synergistic regulation of micro sequence interface and macro bionic structure for superior microwave absorption performance

The synergistic regulation of micro sequence interface and macro bionic structure for superior microwave absorption performance

Investigation of microwave absorption performance of anti-radiation plastic cement brick

The increasing demand for effective anti-microwave radiation materials motivates the exploration of sustainable and eco-friendly alternatives. This research investigates the microwave absorption properties of various brick compositions, including commercial brick (CB) and solid bricks (SB1, SB2 and SB3) incorporating recycled materials, polyethylene terephthalate (PET) and palm oil fuel ash (POFA). The dimension of the developed brick is 200×100×60 mm (length×width×height). The absorption performance of the bricks was measured in 100 mm and 60 mm thickness across the frequency range of 1 to 12 GHz using the naval research laboratory (NRL) free space arch method. At 100 mm thickness, SB3 shows the highest absorption up to-32.2061 dB at 1.98 GHz. At 60 mm thickness, SB1 achieved the maximum absorption at -57.6511 dB at 2.505 GHz. SB2 shows consistent average absorption performance at 15.2064 dB at 100 mm thickness and -19.5 dB at 60 mm thickness respectively. The compressive strength of the brick was measured, and it was shown that SB2 exhibited the highest average compressive strength of 7.17 MPa. Considering the standard wall thickness and brick strength, SB2 shows the most effective performance due to its enhanced composition and consistent performance across frequencies.

Compositional and structural engineering of multicomponent borides hollow microspheres with superior microwave absorption performance

Compositional and structural engineering of multicomponent borides hollow microspheres with superior microwave absorption performance

Tunable Microwave Absorption Performance of Ni-TiN@CN Nanocomposites with Synergistic Effects from the Addition of Ni Metal Elements

This paper presents the synthesis and characterization of Ni-TiN@CN nanocomposites fabricated via arc discharge, followed by dopamine polymerization and pyrolysis. The cubic morphology of the Ni-TiN cores and uniform CN encapsulation were confirmed by structural analyses. Electromagnetic evaluations revealed that the CN shell thickness critically influenced the dielectric dispersion, polarization relaxation and conductive loss. The optimal sample (Ni-TiN@CN-3) achieved a minimum reflection loss of −42.05 dB at 4.06 GHz. The incorporation of magnetic Ni particles introduced a magnetic loss mechanism, while the multiple intrinsic defects within the heterogeneous structure synergistically generated defect dipole polarization and conductive loss. The strategic addition of Ni facilitated the construction of heterogeneous interfaces, which achieved enhanced interface polarization effects. The effective absorption bandwidth (≤−10 dB) reached 14.9 GHz, while the effective absorption bandwidth (≤−20 dB) achieved 6.5 GHz. The optimized CN layer facilitated a synergistic interplay between the dielectric loss and magnetic loss, which ensured balanced impedance matching and attenuation, as well as enhanced electromagnetic wave dissipation. This integrated optimization ultimately endowed the material with exceptional microwave absorption performance through an effective electromagnetic energy conversion. This work highlights Ni-TiN@CN nanocomposites as promising candidates for high-performance microwave absorbers in extreme environments.

Phase and Valence State Engineering of MOFs-Derived Iron Oxide@Carbon Polyhedrons for Advanced Microwave Absorption

MOFs-derived magnetic carbon-based composites are considered to be valuable materials for the design of high-performance microwave absorbents. Regulating phase structures and introducing mixed-valence states within the composites is a promising strategy to enhance their charge transfer properties, resulting in improved microwave absorption performance. In this study, iron oxide components show a temperature-dependent phase evolution process (α-Fe2O3→Fe3O4→Fe3O4/FeO), during which the valence states of iron ions are regulated. The tunable phases modulate the magnetic Fe3O4 component, resulting in enhanced magnetic loss. The changed valence states affect the polarization relaxation by adjusting the electronic structure and tune the electron scattering by introducing defects, leading to enhanced dielectric loss. The microwave absorption properties of iron oxide@carbon composites display phase- and valence state-dependent characteristics. Especially, Fe3O4@C composites exhibit superior microwave absorption properties, ascribed to the improved magnetic/dielectric losses induced by good impedance matching and strong microwave attenuation capacity. The minimum reflection loss of Fe3O4@C composites reaches −73.14 dB at 10.35 GHz with an effective absorption bandwidth of 4.9 GHz (7.69–12.59 GHz) when the absorber thickness is 2.31 mm. This work provides new insights into the adjustment of electromagnetic parameters and microwave absorption properties by regulating the phase and valence state.