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Offers an overview of state of the art passive macromodeling techniques with an emphasis on black-box approaches This book offers coverage of developments in linear macromodeling, with a focus on effective, proven methods. After starting with a definition of the fundamental properties that must characterize models of physical systems, the authors discuss several prominent passive macromodeling algorithms for lumped and distributed systems and compare them under accuracy, efficiency, and robustness standpoints. The book includes chapters with standard background material (such as linear time-invariant circuits and systems, basic discretization of field equations, state-space systems), as well as appendices collecting basic facts from linear algebra, optimization templates, and signals and transforms. The text also covers more technical and advanced topics, intended for the specialist, which may be skipped at first reading. * Provides coverage of black-box passive macromodeling, an approach developed by the authors * Elaborates on main concepts and results in a mathematically precise way using easy-to-understand language * Illustrates macromodeling concepts through dedicated examples * Includes a comprehensive set of end-of-chapter problems and exercises Passive Macromodeling: Theory and Applications serves as a reference for senior or graduate level courses in electrical engineering programs, and to engineers in the fields of numerical modeling, simulation, design, and optimization of electrical/electronic systems. Stefano Grivet-Talocia, PhD, is an Associate Professor of Circuit Theory at the Politecnico di Torino in Turin, Italy, and President of IdemWorks. Dr. Grivet-Talocia is author of over 150 technical papers published in international journals and conference proceedings. He invented several algorithms in the area of passive macromodeling, making them available through IdemWorks. Bjørn Gustavsen, PhD, is a Chief Research Scientist in Energy Systems at SINTEF Energy Research in Trondheim, Norway. More than ten years ago, Dr. Gustavsen developed the original version of the vector fitting method with Prof. Semlyen at the University of Toronto. The vector fitting method is one of the most widespread approaches for model extraction. Dr. Gustavsen is also an IEEE fellow.

Multiple internal reflection-based absorption-dominant stretchable electromagnetic shielding thin film by incorporating liquid metal grid structure is developed.The device demonstrates high electromagnetic shielding effectiveness (SE) (SET of up to 75 dB) with low reflectance (SER of 1.5 dB at the resonant frequency).The shielding properties of the device can be tuned by adjusting the liquid metal patterned grid spaces upon strain.The demand of high-performance thin-film-shaped deformable electromagnetic interference (EMI) shielding devices is increasing for the next generation of wearable and miniaturized soft electronics. Although highly reflective conductive materials can effectively shield EMI, they prevent deformation of the devices owing to rigidity and generate secondary electromagnetic pollution simultaneously. Herein, soft and stretchable EMI shielding thin film devices with absorption-dominant EMI shielding behavior is presented. The devices consist of liquid metal (LM) layer and LM grid-patterned layer separated by a thin elastomeric film, fabricated by leveraging superior adhesion of aerosol-deposited LM on elastomer. The devices demonstrate high electromagnetic shielding effectiveness (SE) (SET of up to 75 dB) with low reflectance (SER of 1.5 dB at the resonant frequency) owing to EMI absorption induced by multiple internal reflection generated in the LM grid architectures. Remarkably, the excellent stretchability of the LM-based devices facilitates tunable EMI shielding abilities through grid space adjustment upon strain (resonant frequency shift from 81.3 to 71.3 GHz @ 33% strain) and is also capable of retaining shielding effectiveness even after multiple strain cycles. This newly explored device presents an advanced paradigm for powerful EMI shielding performance for next-generation smart electronics.

Materials with good flexibility and high conductivity that can provide electromagnetic interference (EMI) shielding with minimal thickness are highly desirable, especially if they can be easily processed into films. Two-dimensional metal carbides and nitrides, known as MXenes, combine metallic conductivity and hydrophilic surfaces. Here, we demonstrate the potential of several MXenes and their polymer composites for EMI shielding. A 45-micrometer-thick Ti₃C₂Tx film exhibited EMI shielding effectiveness of 92 decibels (>50 decibels for a 2.5-micrometer film), which is the highest among synthetic materials of comparable thickness produced to date. This performance originates from the excellent electrical conductivity of Ti₃C₂Tx films (4600 Siemens per centimeter) and multiple internal reflections from Ti₃C₂Tx flakes in free-standing films. The mechanical flexibility and easy coating capability offered by MXenes and their composites enable them to shield surfaces of any shape while providing high EMI shielding efficiency.

HighlightsThe review discusses the key concepts, loss mechanisms and test methods of electromagnetic interference (EMI) shielding.The research progress of polymer matrix EMI shielding composites with different structures is detailedly illustrated, especially their preparation methods and corresponding evaluations.The key scientific and technical problems for polymer matrix EMI shielding composites with different structures are proposed, and their development trend are prospected.With the widespread application of electronic communication technology, the resulting electromagnetic radiation pollution has been significantly increased. Metal matrix electromagnetic interference (EMI) shielding materials have disadvantages such as high density, easy corrosion, difficult processing and high price, etc. Polymer matrix EMI shielding composites possess light weight, corrosion resistance and easy processing. However, the current polymer matrix composites present relatively low electrical conductivity and poor EMI shielding performance. This review firstly discusses the key concept, loss mechanism and test method of EMI shielding. Then the current development status of EMI shielding materials is summarized, and the research progress of polymer matrix EMI shielding composites with different structures is illustrated, especially for their preparation methods and evaluation. Finally, the corresponding key scientific and technical problems are proposed, and their development trend is also prospected.

Using a sample coated with three types of carbon-based paints, namely single-wall carbon nanotube (SWCNTs), carbon black, and graphite, the amount of radio wave absorption for each was measured. SWCNTs proved to have the superior radio wave absorption effect in the millimeter band. Considering the change in the amount of radio wave absorption depending on the coating amount, three different coating thicknesses were prepared for each test material. The measurement frequency was set to two frequency bands of 28 GHz and 75 GHz, and the measurement method was carried out based on Japanese Industrial Standard (JIS) R1679 “Radio wave absorption characteristic measurement method in the millimeter wave band of the radio wave absorber.” As for the amount of radio wave absorption in the 28 GHz band, a maximum amount of radio wave absorption of about 6 dB was obtained when 35 m of CNT spray paint was applied. It was confirmed that the carbon black paint came to about 60% that of the SWCNT, and the graphite paint did not obtain much radio wave absorption even when the coating thickness was changed. Furthermore, even in the 75 GHz band, the radio wave absorption was about 7 dB when 16 μm of CNT spray paint was applied, showing the maximum value. Within these experimental results, the CNT spray paint has a higher amount of radio wave absorption in the millimeter wave band than paints using general carbon materials. Its effectiveness could be confirmed even with a very thin coating thickness of 35 μm or less. It was also confirmed that even with the same paint, the radio wave absorption effect changes depending on the difference in coating thickness and the condition of the coated surface.

HighlightsThe rGH@FeNi/epoxy electromagnetic interference (EMI) shielding composites with regular 3D honeycomb structures were prepared by sacrificial template, freeze-drying and vacuum-assisted impregnation of epoxy resin.The construction of 3D honeycomb structure and electromagnetic synergistic effect significantly increase the EMI shielding effectiveness and reduce the secondary contamination.The rGH@FeNi/epoxy composites possess excellent thermal stability and mechanical properties.With the rapid development of fifth-generation mobile communication technology and wearable electronic devices, electromagnetic interference and radiation pollution caused by electromagnetic waves have attracted worldwide attention. Therefore, the design and development of highly efficient EMI shielding materials are of great importance. In this work, the three-dimensional graphene oxide (GO) with regular honeycomb structure (GH) is firstly constructed by sacrificial template and freeze-drying methods. Then, the amino functionalized FeNi alloy particles (f-FeNi) are loaded on the GH skeleton followed by in-situ reduction to prepare rGH@FeNi aerogel. Finally, the rGH@FeNi/epoxy EMI shielding composites with regular honeycomb structure is obtained by vacuum-assisted impregnation of epoxy resin. Benefitting from the construction of regular honeycomb structure and electromagnetic synergistic effect, the rGH@FeNi/epoxy composites with a low rGH@FeNi mass fraction of 2.1 wt% (rGH and f-FeNi are 1.2 and 0.9 wt%, respectively) exhibit a high EMI shielding effectiveness (EMI SE) of 46 dB, which is 5.8 times of that (8 dB) for rGO/FeNi/epoxy composites with the same rGO/FeNi mass fraction. At the same time, the rGH@FeNi/epoxy composites also possess excellent thermal stability (heat-resistance index and temperature at the maximum decomposition rate are 179.1 and 389.0 °C respectively) and mechanical properties (storage modulus is 8296.2 MPa).

HighlightsBottlenecks for developing polymer based electromagnetic interference (EMI) shielding composites are proposed and inner reasons are discussedPossible directions to break through bottlenecks are raised and recent advances in such directions are introduced.Development trends in the future are foreseen to provide theoretical basis and technical guidance for development of polymer based EMI shielding composites.The rapid development of aerospace weapons and equipment, wireless base stations and 5G communication technologies has put forward newer and higher requirements for the comprehensive performances of polymer-based electromagnetic interference (EMI) shielding composites. However, most of currently prepared polymer-based EMI shielding composites are still difficult to combine high performance and multi-functionality. In response to this, based on the research works of relevant researchers as well as our research group, three possible directions to break through the above bottlenecks are proposed, including construction of efficient conductive networks, optimization of multi-interfaces for lightweight and multifunction compatibility design. The future development trends in three directions are prospected, and it is hoped to provide certain theoretical basis and technical guidance for the preparation, research and development of polymer-based EMI shielding composites.

Ag nanoparticles were in-situ grown on the surface of MXene nanosheets to prepare thermally conductive hetero-structured MXene@Ag fillers. With polyvinyl alcohol (PVA) as the polymer matrix, thermally conductive MXene@Ag/PVA composite films were fabricated by the processes of solution blending, pouring, and evaporative self-assembly. With the same mass fraction, MXene@Ag-III (MXene/Ag, 2:1, w/w) presents more significant improvement in thermal conductivity coefficient (λ) than MXene@Ag, single MXene, Ag, and simply blending MXene/Ag. MXene@Ag-III/PVA composite films show dual functions of excellent thermal conductivity and electromagnetic interference (EMI) shielding. When the mass fraction of MXene@Ag-III is 60 wt.%, the in-plane λ (λ ∥ ), through-plane λ (λ ⊥ ), and EMI shielding effectiveness (EMI SE) are 3.72 and 0.41 W/(m·K), and 32 dB, which are increased by 3.1, 1.3, and 105.7 times than those of pure PVA film (0.91 and 0.18 W/(m·K), and 0.3 dB), respectively. The 60 wt.% MXene@Ag-III/PVA composite film also has satisfying mechanical and thermal properties, with Young’s modulus, glass transition temperature, and heat resistance index of 3.8 GPa, 58.5 and 175.3 °C, respectively.

HighlightsA layered segregated shielding network was organized in porous PBAT/Fe3O4@MWCNTs/Ag composite by scCO2 foaming and scraping techniques.The composite foam achieved an electromagnetic interference (EMI) shielding effectiveness (SE) of up to 68.0 dB and a reflectivity of as low as 23% due to the “absorption-reflection-re-absorption” shielding mechanism.The solid and foamed PBAT/Fe3O4@MWCNTs/Ag composites displayed superior retention (> 92%) of EMI SE even after peeling experiment of 500 times under 100 g weight pressure.The utilization of eco-friendly, lightweight, high-efficiency and high-absorbing electromagnetic interference (EMI) shielding composites is imperative in light of the worldwide promotion of sustainable manufacturing. In this work, magnetic poly (butyleneadipate-co-terephthalate) (PBAT) microspheres were firstly synthesized via phase separation method, then PBAT composite foams with layered structure was constructed through the supercritical carbon dioxide foaming and scraping techniques. The merits of integrating ferroferric oxide-loaded multi-walled carbon nanotubes (Fe3O4@MWCNTs) nanoparticles, a microcellular framework, and a highly conductive silver layer have been judiciously orchestrated within this distinctive layered configuration. Microwaves are consumed throughout the process of “absorption-reflection-reabsorption” as much as possible, which greatly declines the secondary radiation pollution. The biodegradable PBAT composite foams achieved an EMI shielding effectiveness of up to 68 dB and an absorptivity of 77%, and authenticated favorable stabilization after the tape adhesion experiment.

HighlightsThe MXene/CNT/Polyimide aerogel frame with integrated gradient-conductive structure was constructed by MXene/CNT/poly(amic acid) composite inks with different CNT contents via 3D printing technology.The integrated gradient-conductivity and hierarchical porous structure of MXene/CNT/Polyimide aerogel frame rendered excellent electromagnetic interference shielding performance and ultra low reflection.Construction of advanced electromagnetic interference (EMI) shielding materials with miniaturized, programmable structure and low reflection are promising but challenging. Herein, an integrated transition-metal carbides/carbon nanotube/polyimide (gradient-conductive MXene/CNT/PI, GCMCP) aerogel frame with hierarchical porous structure and gradient-conductivity has been constructed to achieve EMI shielding with ultra-low reflection. The gradient-conductive structures are obtained by continuous 3D printing of MXene/CNT/poly (amic acid) inks with different CNT contents, where the slightly conductive top layer serves as EM absorption layer and the highly conductive bottom layer as reflection layer. In addition, the hierarchical porous structure could extend the EM dissipation path and dissipate EM by multiple reflections. Consequently, the GCMCP aerogel frames exhibit an excellent average EMI shielding efficiency (68.2 dB) and low reflection (R = 0.23). Furthermore, the GCMCP aerogel frames with miniaturized and programmable structures can be used as EMI shielding gaskets and effectively block wireless power transmission, which shows a prosperous application prospect in defense industry and aerospace.