- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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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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Electromagnetic Wave Absorbers (Detailed Theories and Applications) || Methods of Absorber Analysis
摘要： The pyramidal absorbers described in Chapter 1 in the classification of electromagnetic (EM)-wave absorber appearance have been extensively used in anechoic chambers and have already reached sufficient technical achievement levels. In addition, various design methods have been proposed so far regarding these pyramidal absorbers, and their design methods have already been broadly established from aspects of both analysis and actual measurement, as discussed in Chapter 1 [1–5]. On the other hand, various application fields have been expected for flat-type absorbers along with the rapid progress of future communication environments. In view of these situations, in this book we mainly focus on single-layer plate-type absorbers and a multilayer-type absorber composed of flat plate absorbers.
关键词： anechoic chambers,single-layer plate-type absorbers,electromagnetic wave absorbers,flat-type absorbers,multilayer-type absorber
更新于2025-09-19 17:13:59
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Electromagnetic Wave Absorbers (Detailed Theories and Applications) || Fundamentals of Electromagnetic Wave Absorbers
摘要： Needless to say, learning the theory and application of wave absorbers entails learning the fundamentals of electromagnetic (EM)-wave engineering itself. In short, this means learning about a broad range of basic matters such as the following: (a) Transmission line theory, which will aid in understanding the fundamental phenomena of EM waves; (b) Analytical methods to learn EM-wave reflection and transmission phenomena; (c) Various behaviors of EM waves; (d) Theory of EM-wave analysis by computer simulation; (e) Basic knowledge of EM-wave materials; (f ) Measurement of EM-wave material constants; (g) The EM-wave environment associated with wave absorbers; (h) Fundamental concepts of artificial materials; (i) Knowledge of EM-wave absorbers that can be assimilated with artificial intelligence (AI) technology, and other matters.
关键词： computer simulation,AI technology,EM-wave engineering,EM-wave transmission,Electromagnetic wave absorbers,artificial materials,transmission line theory,EM-wave reflection,EM-wave materials
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) || Fundamental Theory of <scp>EM</scp> ‐Wave Absorbers
摘要： In this chapter, in order to understand electromagnetic (EM)-wave absorbers, fundamental theories are described in detail from the viewpoints of both transmission line (TL) theory and Maxwell’s equations. A plane EM-wave problem is often treated by replacing it with a TL problem that is equivalent in its plane-wave behavior. With this approach, it becomes easy to understand the performance of some EM-wave devices, the physical meaning, and other aspects without solving Maxwell’s equations as to transverse electromagnetic (TEM)-wave problems. Even in the case of EM-wave absorber problems, they often treat the TL problems in order to understand the operating principles and absorption characteristics.
关键词： TM wave,Maxwell’s equations,transmission coe?cient,multiple re?ections,electromagnetic-wave absorbers,TE wave,transmission line theory,re?ection coe?cient
更新于2025-09-19 17:13:59
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Electromagnetic Wave Absorbers (Detailed Theories and Applications) || Absorber Characteristic Control by Equivalent Transformation Method of Material Constants
摘要： As mentioned in the previous chapters, demands for various EM-wave absorbers are rapidly increasing along with the trends toward complicated electromagnetic environments and the development of higher frequency communication equipment. Generally, it has been considered highly difficult to produce new EM-wave absorbers having a desired absorbing frequency and an absorbing characteristic. One reason for this is that realizing an optimum material constant satisfying the required characteristics becomes difficult when manufacturing an EM-wave absorber. That is, in the conventional method, it often becomes difficult to freely control parameters such as the mixing ratio of the EM-wave absorber’s raw materials, the firing temperature, the pressure, and the material compositions to realize the appropriate absorber. Furthermore, the problems of accurately measuring material constants and maintaining the accuracy of component sizes become important to the EM-wave absorber in high-frequency use, particularly in the millimeter or terahertz band.
关键词： equivalent transformation method of material constants (ETMMC),EM-wave absorbers,millimeter wave,terahertz band,high-frequency communication
更新于2025-09-19 17:13:59
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Electromagnetic Wave Absorbers (Detailed Theories and Applications) || Basic Theory of Computer Analysis
摘要： One of the reasons that a wide variety of EM-wave absorber analyses came to be possible recently is the remarkable progress of modeling and computer simulation technologies. In addition, in actual computer simulation technologies, a number of theoretical analysis methods and means are compounded and systemized. In this chapter, in order to deepen the basic understanding of computer simulation analysis of EM-wave absorbers, the finite-difference time-domain (FDTD) method and finite element (FE) method are explained in detail, including their fundamental principles.
关键词： EM-wave absorbers,FDTD method,Maxwell's equations,Finite element method,Computer simulation
更新于2025-09-19 17:13:59
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Electromagnetic Wave Absorbers (Detailed Theories and Applications) || Fundamental EM‐Wave Absorber Materials
摘要： In this chapter, in order to obtain basic knowledge of carbon materials and ferrite materials, which are typical EM-wave-absorbing materials, their respective characteristics are examined, especially from the viewpoint of molecular and crystal structures. The Jaumann absorber in early stage of the EM-wave absorber was composed of overlaying the material dispersed carbonyl iron to rubber, the resistive sheet, and the dielectric plate, as described in Chapter 1. In this way, since the absorber was invented, carbon-based materials have been mainly used as EM-wave-absorbing materials. On the other hand, copper–zinc-based soft ferrite was invented in 1930 in Japan. However, the nature of this kind of soft ferrite as an EM-wave absorber was unknown for a long time. Magnetic materials typi?ed by ferrite, metallic resistors, and carbon materials used as resistive ?lms are applied to EM-wave absorbers, and they have changed little to this day.
关键词： molecular and crystal structures,EM-wave absorbers,ferrite materials,carbon materials
更新于2025-09-19 17:13:59
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ANALYSIS OF POWER FLOW BY POYNTING VECTORS FOR ELECTROMAGNETIC WAVE ABSORBERS USING FREQUENCY SELECTIVE SURFACES
摘要： The power ?ow for electromagnetic wave absorbers consisting of pattern conductor layers acting as frequency selective surfaces, absorption layers, and short circuit layers was investigated by Poynting vectors. A method was developed to evaluate the ?ow of electromagnetic wave power by an electromagnetic wave absorber upon irradiation with electromagnetic waves. The results indicate that the electromagnetic wave absorption phenomenon involves generation of real power, a real part of the time averaged Poynting vector, which moves horizontally along the pattern surface after the incident wave has irradiated the pattern conductor from the vertical direction, and the direction of power ?ow changes to enter the polymer layer from the pattern interval, causing an accumulation of power inside the polymer layer, followed by absorption, which is converted into heat due to the loss factor.
关键词： Electromagnetic wave absorbers,Absorption layers,Power flow,Frequency selective surfaces,Poynting vectors
更新于2025-09-04 15:30:14