Electromagnetic Energy Loss Research Articles

A mesoscopic numerical analysis method for evaluating the electromagnetic transmission performance of cement mortar with varying sand particle sizes and content

This paper explores the impact of sand content and particle size on the electromagnetic transmission performance (ETP) of mortar samples. This study involves designing mortar samples with a water-cement ratio of 0.4 and varying sand volume content from 0 % to 50 %. Additionally, a mesoscopic finite element model is established to analyze the electromagnetic transmission behavior. The findings indicate that the particle size and content of sand influence the multiple reflections behavior of electromagnetic waves, while the particle size of sand has almost no effect on the electromagnetic transmission coefficient and dielectric response. Although sand enhances the ETP of cement paste, its impact is limited. Furthermore, the study reveals that the distribution of the electromagnetic field remains continuous regardless of sand particle size or content, and is unaffected by the differing dielectric properties of sand and cement paste phases. However, the induced current generated by sand and other phases differs, leading to noticeable variations in dielectric loss. Mesoscopic simulation results clearly demonstrate that cement paste is the primary contributor to electromagnetic energy loss.

Structure and Mechanical Properties of Microwave-Absorbing Co-C Coatings Obtained by Magnetron Sputtering

This article is devoted to the study of microwave-absorbing properties of Co-C coating applied by magnetron sputtering. This article presents the main results of the manufacturing of a Co-C coating by magnetron sputtering, and the evaluation of experimental and computational research data on the relationship between the structure and properties of the obtained films. The structure of Co-C systems has been modeled to control the resulting structures using X-ray diffraction analysis. The structural-phase state of the resulting thin-film Co-C systems and the microwave-absorbing properties of coatings were studied using the transmission line method, consisting of a vector network analyzer, an air coaxial line, a software program, and an external computer. It has been established that on the resulting Co-C film the reflection coefficient in the frequency range of 8.2–12.4 GHz varies in the range of 900 → 718 mU, with reflection losses of −0.86 → −2.57 dB, and a standing wave coefficient of 19 → 6.8. An analysis of the obtained data indicates the presence of losses of electromagnetic energy in the studied frequency range.

All-dielectric ultra-broadband transparent imidazole ionic liquid-based metamaterial absorber with a frustum-shaped structure.

In this study, a frustum-shaped addition was made to a cylindrical absorber unit, utilizing 1-ethyl-3-methylimidazolium dicyanamide ionic liquid (IL) to create a transparent all-dielectric liquid metamaterial absorber (A-D ILMMA). The A-D ILMMA achieved over 90% absorption efficiency across 4.86-50.00 GHz, with a 165% relative absorption bandwidth. It maintained robust performance across various polarization angles and achieved over 77% absorption at incident angles of up to 60°. Owing to the excellent thermal stability of the IL, the A-D ILMMA consistently maintained an absorption rate of over 90% across a temperature range from 25 °C to 100 °C. The high absorption rates were attributed to synergistic impedance matching and electromagnetic energy loss. The experimental results confirmed over 90% absorption in the ultra-broadband range of 7.10 GHz to 40.00 GHz, demonstrating the excellent physicochemical properties of ILs and their potential applications.

Modulating microwave attributes of Ba1−xSrxTiO3 nanoparticles: Insights into strontium concentration, structural intricacies and electromagnetic dynamics

In this pioneering investigation, we meticulously synthesized Ba1−xSrxTiO3 nanoparticles, with Sr concentrations varying between 0.0 and 0.4 at intervals of 0.1, via a refined chemical approach. The crux of our study lies in establishing the intricate correlations between the chemical constitution (primarily Sr concentration), salient structural attributes (encompassing lattice and microstructural parameters), electrical dynamics and consequential microwave characteristics. X-ray diffraction (XRD) analyses reinforced the unity between the average ionic radii of the Ba/Sr ions and the lattice constants. Scanning electron spectroscopy (SEM) furnished insights into the microstructural intricacies, while the nominal chemical composition was ascertained via energy-dispersive X-ray (EDX) spectroscopy. A deep dive into the electrical realm revealed the temperature and field-dependent behaviors of permittivity, tangent losses and polarization. The electromagnetic traits of Ba1−xSrxTiO3 (where 0.0 < x < 0.4) were meticulously delineated by analyzing the experimentally determined S-parameters across a frequency spectrum of 6 to 18 GHz. Our findings elucidate that the predominant losses of electromagnetic wave energy are attributable to aggregated electrical losses, predominantly steered by polarization processes. Our findings demonstrate a significant attenuation in the reflected wave energy, with values spanning from − 14.3 to − 17.1 dB, highlighting the potential of these nanoparticles for cutting-edge applications in electromagnetic interference mitigation.

Multifunctional phase-change composites for green electromagnetic interference shielding and thermal response prepared under the guidance of an impedance matching strategy.

With the advent of the information age, electromagnetic hazards are becoming more serious. In view of environmental protection, green electromagnetic interference (EMI) shielding materials with little or no secondary reflection have become the ideal choice. In this paper, by freeze-drying, high-temperature carbonization, coating and impregnation backfilling, we prepared carbonized Ni-MOF/reduced graphene oxide/silver nanowire-polyimide@polyethylene glycol composites (Ni@C/r-GO/AgNW-PI@PEG) with gradient conductivity based on impedance matching. The impedance matching layer Ni@C/r-GO-300 reduces the reflection of electromagnetic waves from the surface of the material, the dissipation layer Ni@C/r-GO-600 provides excellent electromagnetic wave dissipation capability, and the reflection layer AgNW-PI ensures that the electromagnetic waves are reflected back into the material. Meanwhile, the EMI shielding performance value of Ni@C/r-GO/AgNW-PI@PEG reaches 62.3 dB with an ultra-low reflectivity (R) of 0.04. In CST simulations, the intrinsic mechanism of electromagnetic energy loss within the material is revealed by energy loss density cloud maps. In addition, heat from high-temperature objects is transferred through the highly thermally conductive AgNW-PI membrane to the long-channel Ni@C/r-GO backbone. Therefore, the composites prepared on the basis of impedance matching will accelerate the use of EMI shielding materials for the thermal management of portable electronic devices and battery heat dissipation packaging.

Peculiarities of Transfer and Heat Losses of Electromagnetic Energy in the Two-Wire Overhead Line with Alternating Electric Conduction Current

Peculiarities of Transfer and Heat Losses of Electromagnetic Energy in the Two-Wire Overhead Line with Alternating Electric Conduction Current

Electromagnetic energy transfer processes in effective electro-magneto dynamics of axions

Oscillating and dissipative energy exchange between the electromagnetic and axion fields is investigated in an effective electro-magneto dynamical (EEMD) model theory, implying the coexistence of axions with hypothetic magnetic charges. An exact formula is presented for the energy transfer between the electromagnetic and axionic sectors. In a first example, we compute analytically the homogeneously oscillating electric and magnetic field configurations generated by the combined action of a constant static magnetic field and a periodically oscillating axion condensate. In the second example, the electromagnetic radiative energy loss of a gravitationally bound axion configuration is computed in the EEMD model. As a result, an asymptotic [Formula: see text] temporal increase of the clump size is found also in EEMD.

Graphite/Epoxy-Coated Flaky FeSiCr Powders with Enhanced Microwave Absorption

Flake-shaped FeSiCr (FFSC) material is expected to be a promising microwave absorbent due to its excellent magnetic properties and environmental resistance. By introducing carbon-based materials through suitable coatings, the electromagnetic parameters and energy loss can be tuned to improve the performance of FFSC. A facile solution-blending method was deployed to prepare graphite- and epoxy resin-encapsulated FFSC (FFSC@G/E) powders with a core–shell structure. FFSC@G2000/E showed excellent performance in the X band (8–12 GHz), a minimum reflection loss (RLmin) of −42.77 dB at a thickness of 3 mm and a maximum effective absorption bandwidth (EABmax, RL &lt; −10 dB) that reached 4.55 GHz at a thickness of 2.7 mm. This work provides a route for the production of novel high-performance microwave absorbers.

Multipath Interference Analysis for Low-Power RFID-Sensor Under Metal Medium Environment

Mechanism analysis of the RFID-Sensor communication interference can effectively improve the information collection quality of the perception layer. In our study, multipath Interference analysis of low-power RFID-Sensor under metal medium environment was considered. Firstly, the dual-antenna RFID-Sensor architecture was developed based on low power strategy, the multipath loss model and interference theory under metal medium environment was discussed. Secondly, by full consideration of electromagnetic interference energy loss factors, the time-frequency domain characteristics of electromagnetic signals, such as direct radiation, refraction, diffraction, scattering, absorption and polarization, were analyzed. Thirdly, the normalized electric field strength between the low-power RFID-Sensor with different distance was obtained through simulation/experiment scenario. The distance between the low-power RFID-Sensor and transmitting antennas is represented by <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</i> , when <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</i> is from 1 m to 5 m, the minimum working distance between the RFID-Sensor antenna and the metal medium surface changed from 6.9 mm to 7.0 mm at the frequency of 915 MHz. This paper was conducive for expanding the functions of the perception layer system of the IoT and enhancing the application potential of existing RFID and sensor networks.

Preparation and mechanism analysis of nanocrystalline cellulose-tricalcium silicate paste composite with high electromagnetic transmission performance

The tricalcium silicate (C3S) paste with high electromagnetic transmission performance is prepared by addition of nanocrystalline cellulose (NCC), and the enhancement mechanism of electromagnetic transmission performance is revealed. The water to cement ratio (W/C) and the contents of NCC are 0.5 and 1 wt%-4wt%, respectively. The results show that the electromagnetic transmissivity of the C3S paste improves with an increase in NCC content. At the frequency of 3.94 GHz, when the NCC contents are 3 wt% and 4 wt%, the electromagnetic transmission coefficient increases by 113.85% and 153.6%, respectively. The enhancement mechanisms of electromagnetic transmission performance of NCC-C3S pastes are as follows: (1) the polymerization degree of C–S–H and the Van der Waals force between the globules increase; (2) the total volume proportions of low electromagnetic loss C3S and Ca(OH)2 increase; (3) the conductivity of C3S pore solution and the volume proportions of water decrease; (4) the pore volume proportion of the non-harmful pores for electromagnetic energy loss increases.

Experimental study and mechanism analysis of functional nanocrystalline cellulose to improve the electromagnetic transmission performance of ordinary Portland cement

5G signal transmission can be seriously blocked by cement-based materials, so it is very important to improve the electromagnetic transmission performance (ETP) of cement-based materials. Carboxylated nanocrystalline cellulose (NCC) is used to prepare Ordinary Portland cement paste with high ETP. The water-cement ratio and NCC content of the cement paste are 0.5 and 0–4% respectively. The test results show that the ETP of cement paste increases by 13.9%–90.6%, but the compressive strength of the sample decreases by 7.3%–87.6%. The 2% of NCC content causes the ETP of cement paste increases by 75.6%, while the compressive strength only decreases by 14.6%. The reasons for improvement of ETP are that the electrostatic force between the globule, the polymerization degree and mean chain length of C–S–H, the total volume proportion of phases (calcium hydroxide, ettringite and unhydrated cement) with low dielectric loss and the volume proportion of the no harmful pore for electromagnetic energy loss are increased, the conductivity of cement pore solution and the content of water are decreased.

High-Efficiency and Flexible Inkjet-Printed Quasi Metasurface Harvester for Microwave Power Transfer Application

This paper demonstrates an inkjet-printed quasi metasurface(QMS) flexible harvester for microwave power transfer(MPT). The substrate and radiator are separately based on Polyimide and EGaIn(Eutectic gallium indium alloy, in which the mass fraction of Ga and In are 75.5% and 24.5%, respectively). Due to the high electromagnetic energy loss of flexible materials, the electric field distribution is improved by etching on the transmission structure, consequently, the energy loss of the material is reduced. The simulated results show that under vertical incidence at 5.8 GHz by trench etching operation, the absorption efficiency(AE) and harvesting efficiency(HE) are both increased from 93% and 65% to 99% and 82%, respectively. The measured results show that the maximum HE is up to 78%, more than 60% HE can be maintained under multi-angle incident waves and more than 70% HE can be maintained in different conformal cases.

Constructing a model of the influence of structural and technological inhomogeneities on electromagnetic energy losses in cables based on a twisted pair

The objects of research reported here were cables based on twisted pairs of various designs. The issue of the emergence of additional losses of electromagnetic energy is related to structural and technological inhomogeneities at the technological stage of cable production. The influence of the working capacitance of the twisted pair on the energy losses in the cables has been substantiated. A methodology was proposed for the numerical calculation of the electric field under the condition of ellipticity of the structural elements of the twisted pair. That has made it possible to determine the distortion of the electric field and the effect of inhomogeneities on the working capacitance of a twisted pair of different designs. Specifically, it was shown that for shielded structures with continuous polymer insulation, the distortion of the electric field and the growth of the working capacitance are observed to a greater extent. The need to find technological solutions to reduce the effect of screen ellipticity on cable capacitance has been emphasized. The effectiveness of capacitance regulation in the presence of inhomogeneities has been confirmed, by using foamed insulation to reduce the loss of electromagnetic energy in the cable. The effect of reducing the working capacitance and increasing additional losses under the simultaneous influence of the ellipticity of the electrical insulation and the protective polymer shell has been established, which necessitates the technological process adjustment in the manufacture of twisted pair. An applied aspect of using the results is the possibility of improving the typical technological process of manufacturing twisted pairs to reduce additional losses of electromagnetic energy at the final technological stage of cable production. The adequacy of the numerical studies was confirmed by experimental dependences of the attenuation coefficient and additional energy losses of the unshielded cable in the frequency range up to 100 MHz

Method of calculation of electromagnetic torque and energy losses of three-phase induction motors when powered by a regulated single-phase voltage

Introduction. Single-phase power supply of induction motors is used in public utilities, in microclimate control systems for remote agricultural consumers, in water supply and pipeline transport systems, etc. In practice, there is the use of induction motors with three-phase stator winding in the conditions of single-phase power supply. Starting and operating capacitors are used to enable their operation when powered by a single-phase network. Problem. There are many fairly accurate methods for calculating the characteristics of an induction motor in asymmetric, including single-phase, modes of operation, but they are based on differential equations, which does not allow to obtain analytical expressions for preliminary analysis and synthesis of such systems. Goal. The purpose of this article is to develop the analytical method of definition of electromagnetic torque and energy losses of voltage-regulated three-phase induction motors working according to the scheme of single-phase inclusion with the phase-shifting capacitor. Methodology. The method is based on the theory of symmetric components and analysis of replacement schemes of induction machine in motor and generator modes. Results. The analysis of the obtained data shows that at a constant value of the phase-shifting capacitor capacity induction motor working according to the scheme of single-phase inclusion has a minimum of losses at one value of slip at different values of supply voltage. Therefore, if you keep this slip constant when the load changes, you can achieve a mode of minimizing losses at a constant value of the capacity, optimal for this slip. This shows that the thyristor voltage regulator can be used as an energy-saving element under variable load, while the capacitance of the phase-shifting capacitor can remain constant when changing the load in a wide range provided that this slip is stabilized. Originality. The developed method allows to obtain analytical expressions for comparative analysis of electromagnetic torque and energy losses of three-phase induction motors powered by a single-phase network at different values of the capacity of the phase-shifting capacitor, supply voltage for different variants of schemes for including three-phase induction motors in a single-phase network. Practical value. Based on the developed analytical method, the optimal parameters of phase-shifting capacitors and rational schemes for including three-phase induction motors in a single-phase network can be determined.

Linear and non-linear optical properties of boron carbide thin films

Boron carbide films deposited by PECVD are subjected to post deposition vacuum annealing and plasma treatment for investigation of changes in the structure, linear and non-linear optical properties of the films. Deconvolution of core level XPES spectra of B1s, C1s and O1s indicates changes in the surface chemical states of the constituent atoms after post deposition treatments. Particle size estimated from XRD spectrum is found increasing from 135 to 140 nm after annealing. Envelop method is used to estimate refractive index, extinction co-efficient, and thickness from their measured optical transmission spectra in VIS-NIR region (400–1400 nm). The refractive index value is found to be 1.619, highest for the vacuum annealed boron carbide film. Direct and indirect optical bandgap remains same after vacuum annealing (Eg = 2.84), the plasma treatment causes a slight decrease in the bandgap. 5% decrease in film thickness is observed after post deposition annealing and plasma treatment owing to film densification. Energy loss in the medium measured in terms of tanδ and ELF’s reveals that the vacuum annealing of the film reduces the electromagnetic and electron energy loss in the film. Non-linear refractive index estimated using Ticha and Tichy relation exhibits similar trend as the linear refractive index spectra.

Tau depolarization at very high energies for neutrino telescopes

The neutrino interaction length scales with energy, and becomes comparable to Earth's diameter above 10's of TeV energies. Over terrestrial distances, the tau's short lifetime leads to an energetic regenerated tau neutrino flux, tau neutrino to tau to tau neutrino, within the Earth. The next generation of neutrino experiments aim to detect ultra-high energy neutrinos. Many of them rely on detecting either the regenerated tau neutrino, or a tau decay shower. Both of these signatures can be affected by the polarization of the tau through the energy distribution of the secondary particles produced from the tau's decay. While taus produced in weak interactions are nearly 100 percent polarized, it is expected that taus experience some depolarization due to electromagnetic interactions in the Earth. In this paper, for the first time we quantify the depolarization of taus in electromagnetic energy loss. We find that tau depolarization has only small effects on the final energy of tau neutrinos or taus produced by high energy tau neutrinos incident on the Earth. Tau depolarization can be directly implemented in Monte Carlo simulations such as nuPyProp and TauRunner.

Features of Transmission and Thermal Losses of Electromagnetic Energy in a Two-Wire Overhead Power Line with the Alternating Electric Current of Conductivity

The results of the research related to the establishment of basic features of transmission and thermal (joule) losses of electromagnetic energy in a homogeneous two-wire overhead power line with the metallic wires of eventual sizes (by the radius of r0 and length l0 &gt;&gt;r0) and alternating (impulsive) electric current of conductivity of i0(t) of different peak-temporal parameters are presented. With the view of the quantum-wave nature of electric current of conductivity of i0(t), it was found that in the metallic wires of probed overhead lines there appear the standing transversal electromagnetic waves (EMWs) that cannot be transmitted at the distance of electromagnetic energy. It is demonstrated that from a weak dispersion of the quantized longitudinal electronic de Broglie semi-waves on the crystal-line lattice sites of a metal (alloy) of wires of the investigated line, the thermal losses of energy are spotted on those lattice sites. The features of the influence of the transversal EMWs in the air envi-ronment of the studied lines on the process of transmission in the overhead power lines at a distance of electro-magnetic energy are established.

Annealing effect on Dy: (GeSe2)80(In2Se3)20 thin films - Oscillator, dielectric, absorption and nonlinear parameters

Rare earth doping increases the emission range and is an attractive candidate for sensing applications because of its good infrared properties. Here (Dy) doped (GeSe2)80(In2Se3)20 thin films have been deposited via thermal evaporation and then annealed at different temperatures in order to investigate its effect on various parameters. Refractive index, calculated by drawing lower and upper envelopes, has been used to calculate the Wemple DiDomenico and Sellmeier oscillator parameters. The calculation of dielectric parameters shows a decrease in the loss of electromagnetic energy. Optical energy bandgap (Eg) values increase from 1.86 eV to 2.10 eV. To a good approximation, E0 and Eg follow Tanaka's relation: E0/Eg ≈ 2. The electric modulus and complex impedance have been interpreted to give information about the relaxation phenomenon in the films. The calculated nonlinear refractive index values vary from 5.74 × 1011 esu to 3.45 × 1011 esu which are far higher than the silica glasses.

Study on Microwave Heating Efficiency and Electromagnetic Energy Loss Distribution of Double Layer Magnetite Cement Concrete

Study on Microwave Heating Efficiency and Electromagnetic Energy Loss Distribution of Double Layer Magnetite Cement Concrete

Broadband Polarization‐Insensitive Coherent Rasorber in Terahertz Metamaterial with Enhanced Anapole Response and Coupled Toroidal Dipole Modes

AbstractEnhanced anapole and coupled toroidal dipole moments sustaining the synthesized terahertz (THz) metamaterial innovatively promise for absorption‐transmission‐absorption (ATA) metamaterial rasorber (MMR). The anapole mode, due to the strong interaction of electric and magnetic dipole moments, and Fabry–Pérot resonance are supported by the dumbbell‐shaped apertures topologically distributed in a double‐layer silver plate, thus forming the transmission window with high frequency‐selectivity. Meanwhile, the coupled toroidal dipole moments depending on the toroidal structure can cause destructive and constructive interference in far and near fields, respectively, thus causing much electromagnetic energy loss in a wide band. Combining anapole with toroidal dipole moments, the ATA MMR depending on the THz metamaterial can attain high absorption (over 0.88) at 1.46–2.29 THz with relative absorption bandwidth (RABW) of 44.27%, and at 3.51–4.3 THz the RABW of 20.26%, and simultaneously the transmission (over 0.7) window covering 2.9–3.21 THz, with relative transmission bandwidth (RTBW) of 10.3%. These superior properties of the MMR promise a great potential for practical application in radar and electromagnetic stealth fields. Furthermore, the innovative combination of anapole and toroidal dipole moments in the MMR assists in enriching the theoretical framework and strategically opening up state‐of‐the‐art pathways of multipole electrodynamics.