- 标题
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- 实验方案
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Fabrication of ultra-thin, hydrophobic and flexible electromagnetic wave absorber sheets based on nano-carbon/carbonyl iron in a polypyrrole/silicone rubber matrix
摘要： In this work, electromagnetic (EM) wave absorbing properties of polypyrrole/silicone rubber (PP-SI) filled nano-carbon and carbonyl iron (CI) nanocomposites have been investigated in the X-band. The PP-SR matrix was provided by the incorporation of polypyrrole and liquid silicone rubber in the ratio of 10:90. The PP-SR serves not only as a matrix but also promotes the flexibility and EM wave absorption of the nanocomposite sheets. In the present research, the chemical, morphology, thermal, wetting, absorption, and mechanical properties of the EM wave absorber sheets are investigated. The EM wave absorber sheet with 3 wt% nano-carbon and 37 wt% CI and a thickness of 1 mm, exhibits a minimum reflection loss around ?13 dB at 10.27 GHz. The absorber sheet with an elongation of 520% could be qualified as a superior elastic sheet. The specimen represents higher thermal stability compared with pure SR, and the contact angle of the sheet proved that their surface should be hydrophobic.
关键词： Flexible wave absorbers,Silicone rubber,Polypyrrole,EM wave absorber sheets
更新于2025-09-23 15:21:21
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A flexible and ultra-broadband terahertz wave absorber based on graphenea??vertically aligned carbon nanotube hybrids
摘要： Electromagnetic wave absorbers are essential devices in imaging, wireless communication and energy harvesting systems. In this paper, we propose and experimentally demonstrate a flexible and ultra-broadband terahertz (THz) wave absorber based on graphene-vertically aligned carbon nanotube (G-VACNT) hybrids. The THz absorber consists of Cu/PDMS/graphene/VACNT functional layers on PET substrate. Measured results show a 100% qualified operating bandwidth (i.e., absorptance >0.9) and an average power absorptance of 0.986 within the 0.2-3.0 THz range. The absorber also exhibits good absorption performances for a wide range of incident angles up to 60°, and can function normally in different bending states due to its excellent flexibility. The incoming energy of THz waves absorbed by the G-VACNT hybrids results in a temperature increase whose spatial distribution is corresponding to the profile of incident THz beam, providing an efficient and low cost approach for THz beam profiling, collimation and focusing. This work paves the way for the development of large-scale and broadband THz wave absorbers.
关键词： Vertically aligned carbon nanotube,Ultra-broadband,Graphene,Flexible,Terahertz wave absorber
更新于2025-09-23 15:19:57
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Electromagnetic Wave Absorbers (Detailed Theories and Applications) || Configuration Examples of the <scp>EM</scp> ‐wave Absorber
摘要： In recent years, along with increase in various kinds of demands on the communication environment has become communication systems, more complicated. As a result, the introduction of electromagnetic (EM)-wave absorbers is required in each technical field, especially from the viewpoint of preventing interference and mutual interaction. Regarding the pyramid-type absorber, it is widely used and popularized in anechoic chambers; these technologies have reached a high completion degree. For this reason, in this chapter, EM-wave absorber characteristics are addressed, such as those of the quarter-wavelength absorber, single-layer absorber, and two-layer absorber, while touching upon the implementation principle.
关键词： anechoic chambers,single-layer absorber,EM-wave absorber,two-layer absorber,quarter-wavelength absorber
更新于2025-09-19 17:13:59
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Electromagnetic Wave Absorbers (Detailed Theories and Applications) || Autonomous Controllable‐Type Absorber
摘要： The rapid progress of artificial intelligence (AI) technology is remarkable. With its rapid progress, it seems that development of whole technological fields needs to be considered into while facilitating their association with AI technologies in their thinking about development hereafter. Chapter 9 described how to construct electromagnetic (EM)-wave absorbers on the basis of the equivalent transformation method of material constants (ETMMC) idea as a new absorber configuration concept. This chapter introduces a new concept of “autonomous controllable metamaterial” (ACMM) that can be assimilated with AI technology and various characteristics when applying a part of this material as an EM-wave absorber. This absorber can correspond not only to both TE-wave and TM-wave polarization problems but also to electrical controllable EM-wave absorbers that can satisfy all the conditions needed in an EM-wave absorber. Section 10.1 describes the necessity of this new metamaterial, its proposal background, and its configuration method. In Section 10.2, the implementation methods of ACMM-type absorbers are described. In Section 10.3, the conditions that an absorber should have are summarized, and the methods of realizing these absorbing conditions are investigated from every angle. It is important to know the EM-wave absorber behaviors in an ACMM-type absorber. For this purpose, input impedance investigations are conducted in Section 10.4.
关键词： EM-wave absorber,polarization problems,TE-wave,AI technology,electrical controllable EM-wave absorbers,autonomous controllable metamaterial,TM-wave
更新于2025-09-19 17:13:59
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Electromagnetic Wave Absorbers (Detailed Theories and Applications) || Measurement Methods on <scp>EM</scp> ‐Wave Absorbers
摘要： In order to deepen our knowledge of the electromagnetic (EM)-wave absorber design, it becomes important to accurately know the material characteristics and the characteristics of the absorber itself. In this chapter, after describing the measurement methods of material constants, the measurement methods of EM-wave absorber characteristics are described. In particular, we intend here to explain in detail the measurement methods of material constants, including conventional methods together with analytical methods. In Section 7.1, as the methods of measuring the material constants for wave-absorbing materials, the methods of using a rectangle waveguide, coaxial waveguide, and microwave resonators are described. First, measurement methods based on the standing-wave method using the rectangular waveguide and coaxial waveguide are studied. Second, in the microwave resonator methods for cylindrical cavities, the measurement methods of dielectric constant and conductivity in the lossless case, complex permittivity, and complex permeability are investigated theoretically. In Section 7.2, as a method for measuring the EM-wave absorber characteristics, the method of TEM mode transmission lines such as coaxial waveguides, strip lines, and TEM cells are examined first. Then, the waveguide method, as a special case, is described, along with space standing-wave methods.
关键词： cavity resonator method,EM-wave absorber,TEM mode transmission line,material constants,measurement methods,waveguide method,space standing-wave method,standing-wave method
更新于2025-09-19 17:13:59
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Electromagnetic Wave Absorbers (Detailed Theories and Applications) || Theory of Special Mediums
摘要： In this section, chiral, magnetized ferrite, and metamaterial media are taken up as special media related to the EM-wave absorber and attenuator, and these theoretical treatments of EM fields are described in detail.
关键词： EM-wave absorber,magnetized ferrite,chiral medium,metamaterial,attenuator
更新于2025-09-19 17:13:59
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Constructing excellent electromagnetic wave absorber with dielectric-dielectric media based on 3D reduced graphene and Ag(I)-Schiff base coordination compounds
摘要： The dielectric-dielectric composite (SRGA) for electromagnetic absorber was fabricated via integrating Ag(I)-Schiff base coordination compounds (SSBCC) with three-dimensional reduced graphene aerogel (3D-rGA) powders. SRGA showed excellent electromagnetic wave absorption properties in terms of re?ection loss, absorption band width and absorber thickness. Specially, when the mass ratio of SSBC to 3D-rGA powders was 1:3 (SRGA-25), the maximum value of re?ection loss at 2 mm was up to (cid:1)63.82 dB and the effective frequency bandwidth of 6.28 GHz (10.16e16.44 GHz) at 2.5 mm can be obtained. The mechanism investigation of electromagnetic wave absorption for SRGA showed that the enhanced electromagnetic wave absorption was ascribed to enhanced polarization loss derived from good 3D-conductive-network units of 3D-rGA, abundant interfaces caused by the media heterostructure due to the introduction of SSBCC and the good impedance matching condition. And 3D-rGA based materials might be put into practical application only in powder state due to the very low strength of the buck state. Therefore, the investigation on SRGA in our contribution is considered to be an actual performance evaluation of the materials based on three-dimensional graphene for microwave attenuation. This work also provided a method for fabricating excellent graphene-based electromagnetic wave absorbers by simply mixing a suitable dielectric lossy material, e.g. SSBCC.
关键词： Electromagnetic wave absorber,Schiff base,Composite,Microwave attenuation,Graphene aerogel
更新于2025-09-04 15:30:14