Excellent Electromagnetic Wave Absorption Properties Research Articles

One-step fabrication of a novel fiber-based absorber for flexible, tunable and boosted microwave absorption

The increasingly intricate electromagnetic environment necessitates higher anti-electromagnetic interference capabilities for electronic devices, thereby demanding a flexible absorbing material that can adapt to multiple forms, is lightweight, and exhibits excellent electromagnetic wave (EMW) absorption properties. In this study, we have developed a novel flexible absorbing material (FAM) based on glass-coated amorphous magnetic fibers (SFs) and Dallenbach-like absorbing structures through wet forming technology. By combining high-performance absorbing fiber with textile structures, the FAM demonstrates EMW absorption performance along with lightweight flexibility and shape adaptability. This paper explores the influence of process parameters in wet forming technology on FAM formation; as well as examines the construction of broadband absorbers through structural optimization. A single-layer FAM with a thickness of 1.7 mm (SFs length 8 mm, content 3 g/m2) achieves an impressive reflection loss (RL) value of −60.1 dB at 11.6 GHz. Furthermore, optimized multi-layer FAM attains effective absorption bandwidth (EAB: RL ≤ −5 dB) across a wide range from 3–14 GHz. This work presents a new approach for developing ’lightweight, thin, wide, and strong’ absorbing materials based on fiber and textile structures which holds significant implications for civilian electromagnetic interference protection as well as military electromagnetic stealth technology.

Multiple Tin Compounds Modified Carbon Fibers to Construct Heterogeneous Interfaces for Corrosion Prevention and Electromagnetic Wave Absorption

HighlightsExcellent impedance matching through component modulation engineering.Rich heterogeneous interfaces are constructed to realize excellent electromagnetic wave (EMW) absorption performance.Long-term corrosion protection and excellent EMW absorption properties.

Multi-dimensional, multi-interface Fe3C/carbon sheets/carbon tubes nanoarchitecture towards high-performance microwave absorption

The serious problem of electromagnetic (EM) interference brings growing demand for developing high-performance electromagnetic shielding materials. In this study, three-dimensional (3D) Fe3C/carbon/carbon tubes (Fe3C/C/CT) absorber with multi-heterointerface was prepared by a facile self-propagating followed by chemical vapor deposition (CVD) strategy. Initially, Fe3O4 nanoparticles were anchored onto carbon nanosheets through the self-propagating process. After different etching times with diluted acid, CTs with diverse dimensions and quantities were catalyzed by the modified Fe3O4 catalysts during the CVD approach and grown from the carbon sheets. Such a special nanoarchitecture, which consists of carbon sheets and carbon tubes, acts as the source of dielectric loss. Meanwhile, Fe3C nanoparticles provide magnetic loss, and the abundant interfaces facilitate synergistic electromagnetic loss. Moreover, large numbers of heterointerfaces from the unique multidimensional nanoarchitecture significantly enhance the impedance matching and produce abundant dipole polarization. Ultimately, with etching time of 30 min, the Fe3C/C/CT-30 achieves excellent electromagnetic wave (EMW) absorption property with a minimum reflection loss of −46.4 dB at 10.56 GHz with a thickness of 3.0 mm. When the thickness is 3.57 mm, the effective absorption bandwidth (EAB) can extend up to 4.48 GHz. Moreover, the practical application of the absorbers was evaluated using radar cross-section (RCS) simulation, indicating that Fe3C/C/CT-30 achieves a maximum RCS reduction value of 58 dBm2. The multi-dimensional and multi-heterointerface absorber presented in this work might offer valuable insights for optimizing electromagnetic absorbers.

Magnetic carbon composites derived from biomass with excellent microwave absorption capacity

It is well known that magnetic iron oxide (Fe3O4) and carbon-based materials are good microwave absorbing materials. However, the frequency bands in which Fe3O4 absorbs electromagnetic waves are usually concentrated in the low-frequency region, whereas carbon materials are in the high-frequency region. Therefore, this study aims to deal with the limitation of the absorption bands of these two substances. In this work, this Fe3O4/C composite with high performance microwave absorption was successfully adoption of hydrothermal-calcination process using mangosteen shells as a biomass carbon material, and with a thickness of 1.97 mm, the optimal reflection loss of the sample can reach −67.49 dB, and the frequency band that can be absorbed is 4.32 GHz. The interface polarization, dipolar polarization and eddy current loss in Fe3O4 and carbon materials produce synergistic effects, and the porous conductive network increases the electromagnetic wave transmission path and generates conductive losses, which results in composites with excellent electromagnetic wave absorption properties. The findings indicated that a composite compound of Fe3O4 and carbon-based material was successfully synthesized by hydrothermal method and obtained a materials with outstanding electromagnetic wave absorption properties and high absorption bandwidth.

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

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

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

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

Advances in Carbon Microsphere-Based Nanomaterials for Efficient Electromagnetic Wave Absorption.

Carbon microspheres have indeed shown great promise as effective materials for absorbing electromagnetic waves, particularly in microwave applications. Their unique properties, such as high surface area, porosity, and electronic characteristics, make them ideal candidates for addressing the growing concerns around electromagnetic pollution from electronic devices. By leveraging the properties of these materials, we can work toward creating more efficient and sustainable electromagnetic wave absorption technologies. Recent efforts have focused on synthesizing and investigating carbon microsphere-based electromagnetic wave-absorbing nanomaterials with the ambition of achieving the desired attributes of being thin, light, wide, and robust. This Review first delves into the detailed mechanism of electromagnetic wave absorption, followed by an elucidation of the preparation methods for carbon microsphere-based nanomaterials. Furthermore, it systematically outlines the common methods and strategies employed to improve the microwave absorption capabilities of carbon microspheres, including chemical vapor deposition, emulsion polymerization, hydrothermal methods, and template methods. Lastly, it outlines the challenges encountered by carbon microsphere-based electromagnetic wave absorption nanomaterials and outlines their prospects, mainly morphology change, component hybridization, and elemental doping. This Review aims to provide valuable insights into the creation of carbon microsphere nanomaterials with excellent electromagnetic wave absorption properties.

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.

A novel biomass-derived carbon@ZnO@ZnSe composites for efficient electromagnetic wave absorption

A novel biomass carbon-based ternary composite coated with ZnO and ZnSe was synthesized by activated carbonization and hydrothermal method. The composition, microstructure and electromagnetic wave (EMW) absorption performance and related mechanism of the composites were investigated in detail. The unique coating structure of lamellar ZnO and spherical ZnSe facilitates multiple reflection and scattering of EMWs, thereby enhancing the dissipation of EMW energy. Moreover, the incorporation of highly conductive ZnO and ZnSe not only enhances the polarization loss and conductivity loss of CBP@ZnO@ZnSe composites, but also improves the impedance matching, further optimizing the EMW absorption property greatly. The CBP@ZnO@ZnSe composites exhibited enhanced EMW absorption performance, characterized by a minimum reflection loss of −24.57 dB and an effective absorption bandwidth of 3.43 GHz at 2.89 mm, owing to the synergistic interplay of favorable impedance matching and attenuation ability. In addition, radar cross section simulation results further demonstrated that CBP@ZnO@ZnSe composites have good electromagnetic energy dissipation effect in practical applications. This study not only offers a simple and feasible method for preparing CBP@ZnO@ZnSe composites with excellent EMW absorption properties, but also serves as a reference for the research of ternary composites based on bio-derived carbon.

A Semi-amorphous Ti-BDC-derived Ti/C nanocomposite for efficient electromagnetic wave absorption

Electromagnetic (EM) interference presents a crippling risk to both human health and the dependability of technological devices. Due to their diverse advantages, metal-organic framework (MOF) derivatives have received much attention in developing novel EM wave-absorbing materials. Nevertheless, achieving desirable EM wave absorption capabilities in magnetic carbon-based absorbers through deliberate adjustment of MOFs remains a difficult task. In this study, a novel nanoporous carbon material (TiO2/C) has been successfully synthesized by a semi-amorphous material (Ti-BDC), which has excellent EM wave absorption properties. In detail, the minimum reflection loss (RL) of −49.7 dB and broad effective absorbing bandwidth (EAB) of 4.16 GHz can be reached with an absorbent thickness of 2.2 mm. The improved performance is mostly due to the dipole polarization of the functional groups and the even distribution of the nanoparticles, which form a seamless network. This promotes the dissipation of polarization and dielectric energy at the interface. In addition, the TiO2 nanoparticles on the carbon material improve the impedance matching, further enhancing the material's absorption performance.

Microstructure and EMW absorption properties of PDCs-SiCN(Ti) ceramics with adjustable SiC nanowires and TiC nanocrystallines

Herein, a novel type of ceramic material exhibiting tunable electromagnetic properties was synthesized using the polymer-derived ceramics (PDCs) method. The precursor employed in this process was a tetrabutyl titanate-modified polysilazane, which ultimately led to the formation of PDCs-SiCN(Ti) ceramics. High-temperature annealing (1400 °C-1500 °C) was used to prepare PDCs-SiCN(Ti) ceramics, which exhibited a unique dual nanostructure comprising SiC nanowires and TiC nanocrystals and served as effective nanoabsorbents. The SiC and TiC contents are closely related to the annealing temperature and induced Ti content. After annealing at 1500 °C, the PDCs-SiCN(Ti) ceramics with the typical A + B + C electromagnetic absorbing structure exhibited excellent electromagnetic wave (EMW) absorption properties. The PDCs-SiCN(Ti) ceramics, with a Ti content of 5 wt%, demonstrated an effective absorption bandwidth (EAB) of 3.8 GHz, which encompassed 90.5 % of the X band, despite having a relatively thin impedance matching thickness of only 2.1 mm. The outstanding EMW attenuation capability of the PDC-SiCN(Ti) ceramics can be ascribed to their large specific surface area and defects combined with the high permittivity of dispersed TiC nanocrystals, which facilitates multiple reflections of EMW within the SiCN matrix. Therefore, this work provides a controllable preparation method for PDCs-SiCN(Ti) ceramics with various microwave absorbing phases.

High-performance electromagnetic wave absorption by two-dimensional mesoporous monolayer Ti3C2Tx MXene

Transition metal carbide MXene, with its unique chemical composition, structure and sizeable particular surface area, is widely applied in wave absorption. However, the high conductivity of MXene resulted in an impedance mismatch that prevented electromagnetic waves from entering the material to achieve dissipation, and thus, tuning the intrinsic properties of pure MXene to obtain excellent electromagnetic wave absorption is still a challenge. Here, we strengthen the absorption of electromagnetic waves by generating titanium vacancies through hydrogen peroxide etching and thus forming micro-sized wrinkles with porous MXene. Porous MXene possesses an excellent microstructure and surface state, abundant porous defects, and moderate electrical conductivity, allowing it to achieve well-matched impedance, dipole polarization, and conduction loss, thus inheriting excellent electromagnetic wave absorption (EWA) properties. Therefore, the porous MXene achieves a strong absorption of − 63.31 dB and an adequate absorption bandwidth (EAB) of 6.88 GHz at a matched thickness of 2.39 mm with a fill ratio of 6 wt%.

Abundant vacancies induced high polarization-attenuation effects in flower-like WS2 microwave absorbers

Defect engineering could provide new ideas for the design of transition metal disulfide electromagnetic wave (EMW) absorbers with high performance. Since the effects of dipoles on impedance matching and EMW absorption are crucial for the development of novel absorbers, the polarization attenuation dependence on defect engineering should be understood at micro- and macro-scales. In this paper, it is found that the defect-rich WS2 nanoflowers synthesized by the cold plasma method possess excellent EMW absorption properties. Cold plasma treatment of materials is easy to perform and maintains the original shape of the material to a high degree. The formation of defects results in abundant electrochemically active sites, increased multiple reflection losses, improved dielectric properties and impedance matching in the materials. The RLmin of the defect-rich material with a thickness of 3.19 mm is as high as −54.36 dB at 8.16 GHz, and the effective absorption bandwidth is 4.72 GHz. The results reveal that the formation of defective vacancies enhances the effects of dipole polarization of the material on improving its EMW absorption properties. Thus, this work provides not only a facile preparation route for novel EMW-absorbing materials, but also a new strategy for tunning defects in transition metal disulfides.

Fabrication of Metal–Organic Framework‐Derived LaCo/C‐Decorated Ti3C2Tx Composites with High Electromagnetic Wave Absorption

Thin‐thickness and lightweight electromagnetic wave (EMW) absorption materials are critically needed for stealth technology in the military stealth field. The special structure of a material is important for improving its good EMW absorption. Herein, a series of porous metal–organic framework‐derived LaCo/C‐decorated Ti3C2Tx (LaCo/C/Ti3C2Tx) composites are prepared by carbonization at high temperatures. Impressively, the minimum reflection loss of LaCo/C/Ti3C2Tx–2 is −47.72 dB at 10.26 GHz (thickness 2.3 mm), and the optimal effective absorption bandwidth is 5.45 GHz (thickness 1.9 mm). The excellent EMW absorption properties are due to multiple electromagnetic loss mechanisms, such as polarization loss, magnetic loss, and multiple reflections and scattering. This work provides a new route for the application of Ti3C2Tx‐based derivatives.

Fabrication of hollow Ni/NiO/C/MnO2@polypyrrole core-shell structures for high-performance electromagnetic wave absorption

In response to the increasingly serious problem of electromagnetic wave pollution, there is a growing demand for materials capable of absorbing electromagnetic waves. A crucial strategy involves optimizing the microstructure and composition of these materials. In this study, the Ni/NiO/C/MnO2@PPy (NCMP) composites are successfully fabricated through the combination of hydrothermal method, high-temperature calcination process, chemical method and in situ polymerization. Due to the strong synergistic effect of the dielectric and magnetic components, and good impedance match, the NCMP-40 exhibits excellent electromagnetic wave absorption properties, with an optimal reflection loss (RLmin) of −56.23 dB at a thickness of 3.87 mm, and a high effective absorption bandwidth (EAB) of 6.86 GHz (10.68–17.54 GHz) at a thickness of 1.97 mm covering the entire Ku-band part of the X-band. Moreover, the radar cross section (RCS) attenuation is obtained through a simulation procedure. Compared to the sole perfect electrically conductive (PEC) layer, the PEC layer coated with NCMP-40 achieves an RCS value consistently below −10 dB m2 in the range of −60° < θ < 60°, and an RCS value is −22.0 dB m2 at θ = 0°. The prepared NCMP-40 presented herein shows excellent electromagnetic wave absorption performances. And this study provides a new method for the structural design of electromagnetic wave absorption materials.

Fabrication of polydopamine-coated ZIF-67 derived Co@CN/rGO composite with excellent electromagnetic wave absorption properties

Constructing a reasonable microstructure and component modulation is considered as an effective way to improve the absorption performance of the absorbents. Herein, a series of Co@CN/rGOs composites were obtained via simple pyrolysis of dopamine-coated ZIF-67 loaded graphene oxide (ZIF-67@PDA/GO) at a high temperature. The existence of rGO after thermal treatment effectively improved dielectric loss. The multiple heterogeneous interfaces between rGO and the carbon layers formed by the polydopamine pyrolysis facilitated the interfacial polarization and relaxation. As a result, with only 20 wt% filler content, the RLmin value of Co@CN/10%rGO reached −49.98 dB at 5.50 GHz (low frequency) with a thickness of 4.5 mm. The effective absorption bandwidth increased to 5.70 GHz (10.26–15.96 GHz) by adjusting the thickness to 2.3 mm. This work provides a facile method for the construction of multicomponent nonhomogeneous interfaces and offers a novel strategy for the design of efficient absorbents.

Enhanced electromagnetic wave absorption properties of SiCN(Ni)/BN ceramics by in situ generated Ni and Ni3Si.

In this paper, the SiCN(Ni)/BN ceramic with excellent electromagnetic wave (EMW) absorption performance was successfully prepared. The Ni and Ni3Si were in situ formed by the introduction of nickel acetylacetonate (NA), which effectively improved the impedance matching performance of SiCN(Ni)/BN ceramics. The EMW absorption properties of the SiCN(Ni)/BN ceramics showed a trend of first increasing and then decreasing with the increase in content of NA. When the NA content reached 7 wt%, the impedance matching range of SiCN-7 was optimal. The minimum reflection loss (RLmin) of SiCN-7 reached -53.47 dB at 4.2 mm and the effective absorption bandwidth (EAB) was 2.32 GHz at 3.48 mm. Through the analysis of electrical conductivity, it was found that the proportion of polarization loss in dielectric loss was more than 99%. It is worth noting that the radar cross section (RCS) value of SiCN-7 absorber was lower than that of the perfect electrical conductor (PEC) plate in the range of -90-90°, and showed a larger coverage angle, indicating that it possessed a good practical application prospect in the field of electromagnetic wave absorption.

Tuning the microstructure of porous SiCnw/SiC fabricated by vat photopolymerization 3D printing for electromagnetic wave absorption

SiC is recognized as a viable material for electromagnetic wave (EMW) absorption due to its unique physicochemical properties. However, there are still some challenges at present, such as poor EMW absorption performance and difficulty in the fabrication of complicated structures for optimized EMW properties. Here, we presented a novel strategy through vat photopolymerization (VPP) 3D printing technology and carbothermal reduction to prepare porous SiCnw/SiC ceramics with controlled topologies and excellent EMW absorption properties. The gradient hole structure produced by carbothermal reduction facilitates material impedance matching regulation and improves incident wave multiple scattering as well as the in-situ grown SiCnw acts as the dipole center and improves incident wave dielectric loss. Porous SiCnw/SiC ceramics achieve improved EMW absorption performance with a minimum reflection loss (RL) of −57.67 dB at a thickness of 2.20 mm and with an effective absorption bandwidth (EAB) of 3.93 GHz at a thickness of 2.60 mm, covering almost the whole X-band, demonstrating outstanding EMW absorption properties. Furthermore, it exhibits the potential in the application of EMW absorbing devices with complex structure.

Cobalt-nickel carbonate hydroxide composites achieving excellent electromagnetic absorption and wide bandwidth through incorporation with polypyrrole nanotubes

Electromagnetic absorption composite with prominent absorption properties and wider absorption bandwidth are in urgent desire. Polypyrrole-based composite is a prosperous candidate due to its easiness in synthesis, morphological diversity and controllable conductivity. In the present work, cobalt-nickel carbonate hydroxide (CCH) microwave absorption materials incorporating polypyrrole nanotubes (PNTs) in different loadings (CCH/PNTs) were prepared via a facile template method next to a hydrothermal treatment. The CCH is revealed in a sea-urchin-like morphology and PNTs are dispersed on the surface of the CCH. In light of the unique morphology, large specific surface area and interfaces, the CCH/PNTs composites exhibit excellent electromagnetic wave (EMW) absorption performance and extensive bandwidth of absorption. With a 180 mg loading of PNTs, the composite delivers a minimum reflection loss (RLmin) of − 57.4 dB with an effective absorption bandwidth (EAB) of 5.44 GHz. By tuning the matching thickness, a wide EAB larger than 7 GHz can be obtained in the X-band and Ku-band. The prominent EMW absorption properties can be ascribed to the dielectric loss, the polarization loss and multiple scattering attenuation from the large surfaces and interfaces from PNTs, and the optimization of impedance matching via CCH. The present research can offer an intuitive guide for the conception of microwave absorbers with wide absorption bandwidth.