Synthesis of Si-based KH560/RGO@Fe3O4 composite for improving electromagnetic properties in 2–18 GHz frequency range

2018 ◽  
Vol 30 (2) ◽  
pp. 1626-1636 ◽  
Author(s):  
Yuexuan Li ◽  
Yugang Duan
Keyword(s):  
Electromagnetic Properties ◽  
Frequency Range

scholarly journals Modelling natural electromagnetic interference in man-made conductors for space weather applications

2016 ◽  
Vol 34 (4) ◽  
pp. 427-436 ◽  
Author(s):  
Larisa Trichtchenko
Keyword(s):  
Exact Solution ◽  
Space Weather ◽  
Electromagnetic Interference ◽  
Geomagnetic Storms ◽  
Electromagnetic Properties ◽  
Electromagnetic Response ◽  
Frequency Range ◽  
Geomagnetically Induced Currents ◽  
Geomagnetic Variations ◽  
Wide Range

Abstract. Power transmission lines above the ground, cables and pipelines in the ground and under the sea, and in general all man-made long grounded conductors are exposed to the variations of the natural electromagnetic field. The resulting currents in the networks (commonly named geomagnetically induced currents, GIC), are produced by the conductive and/or inductive coupling and can compromise or even disrupt system operations and, in extreme cases, cause power blackouts, railway signalling mis-operation, or interfere with pipeline corrosion protection systems. To properly model the GIC in order to mitigate their impacts it is necessary to know the frequency dependence of the response of these systems to the geomagnetic variations which naturally span a wide frequency range. For that, the general equations of the electromagnetic induction in a multi-layered infinitely long cylinder (representing cable, power line wire, rail or pipeline) embedded in uniform media have been solved utilising methods widely used in geophysics. The derived electromagnetic fields and currents include the effects of the electromagnetic properties of each layer and of the different types of the surrounding media. This exact solution then has been used to examine the electromagnetic response of particular samples of long conducting structures to the external electromagnetic wave for a wide range of frequencies. Because the exact solution has a rather complicated structure, simple approximate analytical formulas have been proposed, analysed and compared with the results from the exact model. These approximate formulas show good coincidence in the frequency range spanning from geomagnetic storms (less than mHz) to pulsations (mHz to Hz) to atmospherics (kHz) and above, and can be recommended for use in space weather applications.

Electromagnetic properties of porous 3D carbon-based structures in high frequency range

2021 ◽  
pp. 76-83
Author(s):  
E.G. Shashkova ◽  
◽  
N.I. Valunets ◽  
M.I. Demidenko ◽  
A.G. Paddubskaya ◽  
...  
Keyword(s):  
High Frequency ◽  
Electromagnetic Properties ◽  
High Frequency Range ◽  
Frequency Range ◽  
Carbon Based

Electromagnetic Properties of Silica-Coated Planar Anisotropy Carbonyl-Iron Particles in Quasimicrowave Band

2010 ◽  
Vol 160-162 ◽  
pp. 962-967 ◽  
Author(s):  
Rui Han ◽  
Xiang Hua Han ◽  
Liang Qiao ◽  
Tao Wang ◽  
Fa Shen Li
Keyword(s):  
Carbonyl Iron ◽  
Low Frequency ◽  
Electromagnetic Properties ◽  
Complex Permeability ◽  
Frequency Range ◽  
Planar Anisotropy ◽  
Amorphous Sio2 ◽  
Microwave Absorption Properties ◽  
Sio2 Particles ◽  
Minimum Reflection Loss

For the sake of thinner electromagnetic wave absorbers used in quasimicrowave band, planar anisotropy carbonyl-iron (PACI) coated with amorphous SiO2 particles as absorber and paraffin as matrix were prepared. The complex permeability, complex permittivity and microwave absorption properties were investigated in the frequency range of 0.1-18 GHz. Both the real parts of permeability and permittivity are increased with the increasing of PACI/SiO2 particles volume concentrations. The minimum reflection loss shifts to the low frequency region with increase in PACI/SiO2 particles volume concentrations. The decrease of matching frequency could be well explained by the increasing of and . The PACI/SiO2 core-shell material exhibits great potential in application absorbers in quasimicrowave frequency range.

Magnetic Properties of Manganese-Titanium Substituted Barium Ferrite Ba(TiMn)xFe12-2xO19(x=0.0, 0.5, 1.0, 1.5, 2.0) Prepared by the Molten Salt Method

2010 ◽  
Vol 434-435 ◽  
pp. 240-243 ◽  
Author(s):  
Hai Feng Li ◽  
Rong Zhou Gong ◽  
Hao Luo ◽  
Jun Zhou ◽  
Li Ren Fan ◽  
...  
Keyword(s):  
Hysteresis Loop ◽  
Molten Salt ◽  
Barium Ferrite ◽  
Magnetic Hysteresis ◽  
Magnetic Hysteresis Loop ◽  
Electromagnetic Properties ◽  
Molten Salt Method ◽  
Frequency Range ◽  
X Ray Diffraction ◽  
X Ray

M-type hexaferrites Ba(TiMn)xFe12-2xO19 (x=0 to 2) powders were synthesized by molten salt method. X-ray diffraction, scanning electron microscope and vibrating sample magnetometer were used to analyze the structures and electromagnetic properties. The results showed that, the magnetoplumbite structures for all samples were formed. Magnetic hysteresis loop measurements of the Ba(TiMn)xFe12-2xO19, exhibitted that the saturation magnetization (Ms), the remanent magnetization (Mr) and the coercitivity (Hc) of compounds depended strongly on the chemical composition of materials. The maxium values of Ms (52.68emu/g) and Mr (32.89emu/g) of the compounds were found at x=0.5; however, the values of Hc and the areas of magnetic hysteresis loop of compounds decreased with increasing the value of x. The Ba(TiMn)1.5Fe9O19/paraffin wax composites containing 40vol% of doped barium ferrite exhibitted good absorption performances in the frequency range of 2–14 GHz.

ESTIMATION OF ERROR IN MEASURING THE DEPTH OF SURFACE CRACKS BY THE ELECTROPOTENTIAL METHOD ON AN ALTERNATING CURRENT

2020 ◽  
pp. 36-46
Author(s):  
P. N. Shkatov ◽  
I. G. Kuzub ◽  
A. A. Ermolaev
Keyword(s):  
Test Sample ◽  
Alternating Current ◽  
Electromagnetic Properties ◽  
Specific Electrical Conductivity ◽  
Measuring Error ◽  
Surface Cracks ◽  
Frequency Range ◽  
Estimation Of Error ◽  
The Difference ◽  
Free Area

The study carried out research on the error in measuring the depth of surface cracks by the electropotential method on an alternating current with a variation in the magnetic permeability and specific electrical conductivity of the metal. The measuring error appear from the difference between the electromagnetic properties of the metal of the sample used to obtain the calibration dependences and the properties of the metal of the tested object. The research conducted by the method of the finite element. The analysis of the dependences of the electropotential signal in the frequency range for the defect-free area and the area with a surface crack is carried out. The study of the error in measuring the depth h, that depends on the frequency of the transmitted current and the value of h. The comparison of the errors arising from various methods of choosing the calibration characteristics is performed, including the comparison of the equality of electropotential signals in the defect-free areas of the tested area and the test sample selected for calibration.

Electromagnetic Characteristics of Iron-Based Microwave Absorbing Materials

2011 ◽  
Vol 479 ◽  
pp. 106-111
Author(s):  
R.B. Yang ◽  
K.Y. Juan ◽  
Chien Yie Tsay ◽  
W.F. Liang ◽  
Chung Kwei Lin
Keyword(s):  
Complex Permittivity ◽  
Resonant Cavity ◽  
Electromagnetic Properties ◽  
Frequency Range ◽  
Microwave Absorbing Materials ◽  
Absorbing Materials ◽  
Permittivity And Permeability ◽  
Electromagnetic Characteristics ◽  
Iron Based ◽  
Microwave Absorbing

Nowadays human are exposed to an environment filling with electromagnetic waves over a wide frequency range. The electromagnetic properties of microwave absorbing materials plays an important role in the performance of civilian electromagnetic interference (EMI) shielding at low frequency range and military stealth technology at high frequency one. The electromagnetic properties include complex permittivity and permeability and its combination determines the electromagnetic wave absorption ability of a material. Complex permittivity and permeability can be measured by three different methods, i.e., free-space method, coaxial/waveguide method, and resonant cavity perturbation method. The first one requires a large space, expensive equipment, and not suitable for academic usage. In the present study, using coaxial/waveguide and resonant cavity perturbation methods, electromagnetic characteristics of iron-based microwave absorbing materials will be obtained and its microwave absorption performance will be investigated. In addition, a comparison between the measurements by these two methods will be addressed.

Preparation and Electromagnetic Properties of CIP/SiO2/PANI Composites

2013 ◽  
Vol 834-836 ◽  
pp. 187-190
Author(s):  
Ming Ming Wang ◽  
Zhong Lun Zhang ◽  
Wan Jun Hao ◽  
Guo Yan Hou ◽  
Zhi Jun Xin ◽  
...  
Keyword(s):  
Dielectric Loss ◽  
In Situ Polymerization ◽  
Magnetic Loss ◽  
Electromagnetic Properties ◽  
Complex Permeability ◽  
Core Shell ◽  
Network Analyzer ◽  
Frequency Range ◽  
Xrd Patterns

CIP particles first were coated with SiO2 shell by the Stober process , then grafted the polyaniline by in-situ polymerization to prepare CIP/SiO2/PANI core-shell composites. The CIP/SiO2/PANI composites are composed the dielectric loss properties with the the magnetic loss properties, the morphologystructure and electromagnetic properties are characterized by SEMXRD and vector network analyzer, respectively. It is observed that SiO2 and PANI are on the surface of CIP particles, XRD patterns further confirm that the CIP/SiO2/PANI composites are synthesized successfully, and that interaction between components exist in the polymerization. In comparison with CIP, the complex permittivity of CIP/SiO2/PANI composites have certain enhancement in 2-18GHz frequency range, but it has a very small impact on the complex permeability.

Electromagnetic Properties of W – Hexaferrites Composites with Magnetic Texture

2014 ◽  
Vol 1040 ◽  
pp. 29-33 ◽  
Author(s):  
Dmitry V. Wagner ◽  
Olga Dotsenko ◽  
Olga A. Ulyanova
Keyword(s):  
Composite Materials ◽  
Magnetic Materials ◽  
Barium Ferrite ◽  
Polymer Materials ◽  
Electromagnetic Properties ◽  
Frequency Range ◽  
Magnetic Texture

In this article the possibility of production of composite materials with magnetic texture are discussed. For texturing of magnetic polymer materials the device was made. The W-type hexaferrites were synthesized using a standard ceramic technique. Magnetic materials with a texture based on barium ferrite were obtained. The electromagnetic properties of texture and non texture composites were measured in microwave. It was shown, that imaginary permeability of an isotropic sample 1.3 times more that sample with texture in a frequency range of 0.5 – 4 GHz.

scholarly journals Effect of Stripline Number on Resonant Frequency of Hexagonal Split Ring Resonator Metamaterial

2020 ◽  
Vol 9 (1) ◽  
pp. 26-30
Author(s):  
Romi Fadli Syahputra ◽  
Yan Soerbakti ◽  
Riad Syech ◽  
Erman Taer ◽  
Saktioto Saktioto
Keyword(s):  
Electromagnetic Field ◽  
Resonant Frequency ◽  
Ring Resonator ◽  
Negative Refractive Index ◽  
Split Ring Resonator ◽  
Electromagnetic Properties ◽  
Strip Line ◽  
Frequency Range ◽  
Split Ring ◽  
Resonant Frequency Shift

Piranti-piranti elektronik maupun optoelektronik yang efisien dan responsif saat ini tengah masif dikembangkan dalam beragam bentuk dan jenis. Meta-material merupakan rancangan optoelektronik yang unik dengan sifat elektromagnetik yang tidak ditemukan secara alami, salah satunya adalah peristiwa indeks bias negatif. Eksplorasi terhadap banyak ragam struktur metamaterial sangat penting dilakukan untuk mengidentifikasi karakteristik tiap struktur. Salah satu struktur metamaterial yang menarik dikaji adalah bentuk heksagonal. Penelitian ini menginvestigasi karakteristik frekuensi resonan dan distribusi medan elektromagnetik metamaterial split ring resonator heksagonal (SRR-H) yang dikombinasikan dengan stripe line (SL) berupa logam tembaga. Lebih lanjut, jumlah SL divariasikan dari 0 - 5 unit dan disimulasikan dalam medium udara dalam rentang frekuensi 1 – 7,5 GHz. Hasil simulasi menunjukan adanya pergeseran frekuensi resonan untuk tiap penambahan SL dalam rentang frekuensi 4,31 – 5,82 GHz. Sebaran medan listrik cenderung terpusat pada cincin resonator sedangkan medan magnet cenderung terdistribusi pada SL. Desain metamaterial SRR-H dengan 3 SL memberikan respon disipasi energi yang terkecil dengan medan E maksimum 2,59 kV×m-1 dan medan H maksimum 8,69 A×m-1. Desain SRR-H ini cukup potensial untuk diaplikasikan sebagai antena gelombang elektomagnetik yang efisien dan juga sebagai biosensor. Efficient and responsive electronic and optoelectronic devices are currently being massively developed in various forms and types. Metamaterial is a unique optoelectronic design with electromagnetic properties that are not found naturally, one of its properties is a negative refractive index. Exploration of different types of metamaterial structures is very important to identify the characteristics of each structure. One of the interesting metamaterial structures is a hexagonal shape. This research investigates the resonant frequency characteristics and electromagnetic field distribution of split-ring resonator (SRR-H) hexagonal-shaped metamaterial which is combined with the copper stripe line (SL). Furthermore, the number of SL is varied from 0 to 5 units and simulated in the air medium in frequency range of 1 - 7.5 GHz. The simulation results show a resonant frequency shift occurred for each SL combination in the 4.31 - 5.82 GHz frequency range. The distribution of the electric field tends to be concentrated on the resonator while the magnetic field tends to be distributed on the SL. The SRR-H metamaterial with 3 SL provides the smallest energy dissipation response with a maximum E field of 2.59 kV×m-1 and a maximum H field of 8.69 A×m-1. The SRR-H design is potential enough to be applied as an efficient electromagnetic wave antenna and also as a biosensor.Keywords: Metamaterials, SRR-H, strip line, resonant frequency, electromagnetic field

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