scholarly journals Mechanical and electromagnetic pro perties of shields on the base of needle-punched material with conductive and dielectric coatings

2019 ◽  
Vol 64 (1) ◽  
pp. 44-50 ◽  
Author(s):  
H. D. A. Abdulhadi ◽  
A. S. Belousova ◽  
A. M. Prudnik ◽  
L. M. Lynkou
Keyword(s):  
Reflection Coefficient ◽  
Electromagnetic Radiation ◽  
Surface Resistance ◽  
Electromagnetic Compatibility ◽  
Short Circuit ◽  
Frequency Range ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Dielectric Coatings ◽  
Radiation Shields

The results of the development of electromagnetic radiation shields with flexibility and minor weight and size parameters are presented. Needle-punched material was chosen as the basis for the shields of electromagnetic radiation, which was coated with conductive or dielectric coatings. It has been proved that when applied to a needle-punched material of thin (up to 5 mm) conductive or dielectric coatings, the ultimate strength increases to 5–10 kgf/mm2 and the surface resistance decreases to 0.05 MOhm/sq, while the weight and size parameters of the shields do not change significantly. It was shown that the frequency dependencies of the reflection and transmission coefficients correlate for coatings of various types. A sample of an electromagnetic radiation shields based on a needle-punched coated material consisting of powdered shungite has a reflection coefficient measured in the short circuit mode is about –22.8 dB in the 2–4 GHz frequency range, which allows to use this material to ensure electromagnetic compatibility, information security and personnel protection from electromagnetic radiation.

scholarly journals Electromagnetic radiation shielding composite coatings based on powdered alumina and ironoxide

Doklady BGUIR ◽  
2021 ◽  
Vol 19 (3) ◽  
pp. 104-109
Author(s):  
D. I. Penialosa Ovalies ◽  
O. V. Boiprav ◽  
M. V. Tumilovich ◽  
L. M. Lynkou
Keyword(s):  
Iron Oxide ◽  
Electromagnetic Radiation ◽  
Electromagnetic Compatibility ◽  
Composite Coatings ◽  
Radiation Shielding ◽  
Frequency Range ◽  
Reflection And Transmission ◽  
Powdered Iron ◽  
Transmission Coefficients ◽  
Experimental Substantiation

The  article  presents  the  results  of  experimental  substantiation  of  the  method  for  improving the shielding  properties  of  composite  coatings  based  on  powdered  alumina  (electrocorundum,  alum  earth), which  consists  in  modifying  the  composition  of  such  coatings  by adding  to  it  powdered  iron  oxide. This experimental substantiation consisted in the development of the technique for obtaining composite coatings based on powdered alumina and iron oxide, the manufacture of the experimental samplesusing the developed technique,  measurements  of  electromagnetic  radiation  reflection and  transmission  coefficients  values in the frequency range 0.7…17.0 GHz of the manufactured samples; implementation of the comparative analysis of the measured values with the similar values typical for the composite coatings filled with powdered alumina oxides, and composite coatings with the fillers such as powdered iron oxide. The obtained results revealed that by  adding  powdered  iron  oxide  to  the  composite  coatings  based  on powdered  alumina  oxides,  it  is  possible to reduce by 1.0…8.0 dB their electromagnetic radiation transmission coefficient values in the frequency range 0.7…17.0 GHz. In addition, we found that the implementation of the proposed method allows one to decrease by  2.0…20.0  dB  the  electromagnetic  radiation  reflection  coefficient  values  in  the  specified  frequency  range of the considered composite coatings, if such are applied to metal substrates. We propose to use the composite coatings, obtained on the base of the substantiated method, in order to ensure the electromagnetic compatibility of radio-electronic equipment.

scholarly journals ELECTROMAGNETIC RADIATION REFLECTION AND TRANSMISSION CHARACTERISTICS OF TWO-LAYER STRUCTURES BASED ON TRANSITION METAL OXIDES

Doklady BGUIR ◽  
2019 ◽  
pp. 93-100
Author(s):  
O. V. Boiprav ◽  
N. V. Bogush ◽  
L. M. Lynkou
Keyword(s):  
Surface Layer ◽  
Transition Metal ◽  
Metal Oxides ◽  
Electromagnetic Radiation ◽  
Transition Metal Oxides ◽  
Reflection And Transmission Coefficients ◽  
Frequency Range ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Layer Structures

The aim of the work, the results of which are presented in the framework of the article, was to study the of electromagnetic radiation interaction laws in the frequency range 0.7…17 GHz with two-layer structures, the surface layer of which was made using powdered titanium dioxide, and the inner layer was made using a powder material based on oxide ferric iron. The thickness of the layers of the studied structures varied from 0.3 to 1 cm. To achieve this goal, theobjectives associated with the development of a methodology for the manufacture of multilayer structures based on composite materials containing transition metal oxides, as well as with the measurement of such structures samples electromagnetic radiation reflection and transmission coefficients in the frequency range 0.7...17 GHz. These measurements were carried out using a panoramic meter of reflection and transmission coefficients SNA 0.01–17. Based on the obtained measurement results, it was shown that in the frequency range 0.7…2 GHz, the lowest values of electromagnetic radiation reflection coefficient, reaching –20 dB, are characterized by structures whose surface layer thickness is 1 cm, and in the range 2 ... 17 GHz – structures, thickness the surface layer of which is 0.5 or 1 cm (depending on the thickness of the inner layer). The values of electromagnetic radiation transmission coefficient in the frequency range of 0.7...17 GHz of such structures reach –23 dB. Based on the results of the study, it is proposed to use the considered structures in the process of creating shielded rooms or improving the latter (for example, in cases, when it's necessary to reduce the level of passive interference in rooms shielded with metal materials).

Gradient structures of Ni – Zn ferrites for electromagnetic radiation protection devices

2021 ◽  
Vol 5 ◽  
pp. 39-46
Author(s):  
V. V. Karanskij ◽  
◽  
S. V. Smirnov ◽  
A. S. Klimov ◽  
E. V. Savruk ◽  
...  
Keyword(s):  
Electron Beam ◽  
Electromagnetic Radiation ◽  
Radiation Protection ◽  
Electromagnetic Compatibility ◽  
Protective Coatings ◽  
Frequency Range ◽  
Near Surface ◽  
Zn Ferrite ◽  
Absorbing Materials ◽  
Plasma Electronic

Increasing the reliability requirements for electromagnetic compatibility of electronic equipment requires the creation of protective coatings that absorb electromagnetic radiation or the development of new radio-absorbing materials. In the frequency range up to 1 GHz, radio-absorbing materials based on Ni – Zn ferrites are of the greatest interest. The absorption of electromagnetic radiation by ferrites occurs due to resonant phenomena at the level of domains and atoms. Improving the performance of ferrites is possible by modifying their surface properties. In this paper, gradient structures for electromagnetic radiation protection products are obtained by treating the surface of Ni – Zn ferrite samples with a low-energy electron beam. To generate the electron beam, a unique development was used — a forevacuum plasma electronic source that allows forming and transporting a beam with a power density of up to 105 W/cm2 under conditions of high pressure and high gas release. As a result of processing, gradient structures were found on the surface of ferrites. A theoretical analysis and experimental study of the obtained structures “non – magnetic conductor – ferrite”, characterized by an increased attenuation coefficient and a reduced reflection coefficient of electromagnetic radiation in the frequency range from 0.5 to 2.5 GHz. The possibility of obtaining near-surface layers depleted in zinc with increased electrical conductivity and reduced magnetic permeability is shown.

scholarly journals Estimation of S-parameters and dielectric permittivity of quartz ceramics samples in millimeter waveband

Doklady BGUIR ◽  
2021 ◽  
Vol 19 (7) ◽  
pp. 65-71
Author(s):  
N. A. Pevneva ◽  
D. A. Kondrashov ◽  
A. L. Gurskii ◽  
A. V. Gusinsky
Keyword(s):  
Dielectric Constant ◽  
Dielectric Permittivity ◽  
Ceramic Materials ◽  
Reflection And Transmission Coefficients ◽  
Frequency Range ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Higher Order Modes ◽  
S Parameters ◽  
The Fourier Transform

A modified Nicholson – Ross – Weir method was used to determine complex parameters and dielectric permittivity of ceramic materials in the range 78.33–118.1 GHz. The measuring equipment is a meter of complex reflection and transmission coefficients, a waveguide measuring canal with a special measuring cell, consisting of two irregular waveguides and a waveguide chamber between them, which provides insignificant influence of higher-order modes. The dependences of the amplitude and phase of the reflection and transmission coefficients on frequency were obtained experimentally for fluoroplastic and three ceramic samples in the frequency range 78.33–118.1 GHz. The obtained S-parameters are processed according to an algorithm that includes their averaging based on the Fourier transform in order to obtain the values of the dielectric permittivity. Fluoroplastic was used as a reference material with a known dielectric constant. The dielectric constant of fluoroplastic has a stable value of 2.1 in the above mentioned frequency range. The dielectric constant of sample No. 1 varies from 3.6 to 2.5 at the boundaries of the range, sample No. 2 – from 3.7 to 2.1, sample No. 3 – from 2.9 to 1.5. The experimental data are in satisfactory agreement with the literature data for other frequencies taking into account the limits set by the measurement uncertainty.

Reflection and Transmission Coefficients for Two- and Three-Dimensional Quantum Wires

1997 ◽  
Vol 11 (23) ◽  
pp. 2777-2790 ◽  
Author(s):  
M. Razavy
Keyword(s):  
Reflection Coefficient ◽  
Quantum Wires ◽  
Three Dimensional ◽  
Variable Cross Section ◽  
Wave Number ◽  
Variable Cross ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Matrix Differential Equations ◽  
Matrix Differential

The problem of a quantum wire connected smoothly on both sides to leads of variable cross section is studied. A method for solving this problem in terms of a set of nonlinear first order matrix differential equations for the variable reflection amplitude is discussed. The reflection coefficient obtained in this way is directly related to the conductivity, and is calculated as a function of the energy of the ballistic electrons. This formulation can be applied to three-dimensional as well as two dimensional quantum wires. For two specific cases the reflection coefficient is obtained as a function of the wave number of the incident electron, and the contribution of quantum tunneling to the transmission in each case is demonstrated. Also a model with a dissipative force is introduced and its effect on the transmission of the electrons is investigated.

scholarly journals Influence of water content of expanded clay on the reflection coefficient of electromagnetic shild

2021 ◽  
Vol 66 (1) ◽  
pp. 93-100
Author(s):  
T. V. Borbot’ko ◽  
S. E. Savanovich
Keyword(s):  
Reflection Coefficient ◽  
Moisture Content ◽  
Electromagnetic Radiation ◽  
Pore Size ◽  
Operating Frequency ◽  
Reflection Coefficients ◽  
Frequency Range ◽  
Operating Frequency Range ◽  
Influence Of Water ◽  
The Relationship

The regularities of the influence of the moisture content of expanded clay on the values of the reflection coefficient of electromagnetic radiation (EMR) of this material in the frequency range of 1–17 GHz have been established. The relationship between the size of fractions (pore size) of expanded clay and the operating frequency range of the EMR screen samples has been determined. It is shown that a twofold increase in the moisture content of expanded clay with fractions of 1…4 and 10…20 mm provides an extension of the operating frequency range of the EMR shield samples made on the basis of this material, with a decrease in the reflection coefficient of the test samples by 1.7 and 3 times, respectively. It was found that an increase in the moisture content of expanded clay from 19 to 40 % with a decrease in the size of its fractions from 10…20 to 1…4 mm and a pore size from 0.1…0.2 to 0.01…0.06 mm provides a decrease in the values of the reflection coefficient of EMR screen samples at frequencies of 7.7–17.0 GHz, and an increase in the size of expanded clay fractions from 1…4 to 10…20 mm with an increase in the size of its pores from 0.01…0.06 to 0.1…0.2 mm provides a decrease in the values of the reflection coefficient of EMR screen samples at frequencies of 1.0–7.7 GHz. It is shown that the practical use of these regularities makes it possible to form EMR screen samples with reflection coefficients from –2.8 to –22.0 dB in the frequency range 1–17 GHz, which makes it possible to recommend them for use when creating shielded rooms.

scholarly journals Радиоэкранирующие свойства никельсодержащего активированного угля

2019 ◽  
Vol 45 (12) ◽  
pp. 52
Author(s):  
О.В. Бойправ ◽  
Х.А.Э. Айад ◽  
Л.М. Лыньков
Keyword(s):  
Activated Carbon ◽  
Electromagnetic Radiation ◽  
Chemical Deposition ◽  
Powdered Activated Carbon ◽  
Frequency Range ◽  
Carbon Nanocomposites ◽  
Water Solutions ◽  
Nickel Particles ◽  
Radiation Shields

The possibility of metal-carbon nanocomposites synthesis by chemical deposition of nickel particles on powdered activated carbon has been shown. The regularities of the interaction of electromagnetic radiation in the frequency range 8–12 GHz with these nanocomposites have been investigated depending on the water solutions composition used in the process of their synthesis. Based on the results of such study, the prospect of metal-carbon nanocomposites using for the manufacture of effective electromagnetic radiation shields and radioabsorbing materials has been proved.

THE REFLECTION OF WAVES IN A GENERALIZED EPSTEIN PROFILE

1965 ◽  
Vol 43 (5) ◽  
pp. 921-934 ◽  
Author(s):  
R. Burman ◽  
R. N. Gould
Keyword(s):  
Refractive Index ◽  
Wave Equation ◽  
Reflection Coefficient ◽  
Approximate Formula ◽  
Reflection And Transmission Coefficients ◽  
Stratified Medium ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Special Case ◽  
Reflection Of Waves

Epstein (1930) and Rawer (1939) studied the reflection of waves in a stratified medium by transforming the hypergeometric equation into the wave equation. A particular case of the Epstein profile is a symmetrical layer. Considerable attention has been given in the literature to this case as well as to symmetrical layers with certain other profiles of the refractive index. In the present paper a generalized Epstein profile is considered and the reflection and transmission coefficients are obtained. The special case in which the refractive index tends to the same constant value on either side of a layer is then discussed. The symmetrical Epstein profile is a special case of this layer which, in general, is asymmetrical. Particular attention is given to a layer differing only slightly from the symmetrical Epstein layer, a simple approximate formula for the reflection coefficient being derived.

scholarly journals Interaction of electromagnetic radiation in the 20–200 GHz frequency range with arrays of carbon nanotubes with ferromagnetic nanoparticles

2015 ◽  
Vol 6 ◽  
pp. 1056-1064 ◽  
Author(s):  
Agylych Atdayev ◽  
Alexander L Danilyuk ◽  
Serghej L Prischepa
Keyword(s):  
Carbon Nanotubes ◽  
Electromagnetic Radiation ◽  
Frequency Dependence ◽  
Shell Morphology ◽  
Magnetic Nanocomposite ◽  
Core Shell ◽  
Ferromagnetic Nanoparticles ◽  
Frequency Range ◽  
Reflection And Transmission

The interaction of electromagnetic radiation with a magnetic nanocomposite based on carbon nanotubes (CNT) is considered within the model of distributed random nanoparticles with a core–shell morphology. The approach is based on a system composed of a CNT conducting resistive matrix, ferromagnetic inductive nanoparticles and the capacitive interface between the CNT matrix and the nanoparticles, which form resonance resistive–inductive–capacitive circuits. It is shown that the influence of the resonant circuits leads to the emergence of specific resonances, namely peaks and valleys in the frequency dependence of the permeability of the nanocomposite, and in the frequency dependence of the reflection and transmission of electromagnetic radiation.

scholarly journals EVALUATION OF HYDRAULIC PERFORMANCE OF WAVE DISSIPATING BLOCK USING POROSITY

2020 ◽  
pp. 29
Author(s):  
Susumu Araki ◽  
Daiki Watanabe ◽  
Shin-ichi Kubota ◽  
Masaya Hashida
Keyword(s):  
Reflection Coefficient ◽  
Transmission Coefficient ◽  
Hydraulic Performance ◽  
Reflection And Transmission Coefficients ◽  
Reflection And Transmission ◽  
Transmission Coefficients

The reflection and transmission of wave dissipating work mainly depend on the shape and porosity of wave dissipating block. However, the influence of the shape and porosity of wave dissipating block on the reflection and transmission has not been investigated sufficiently. The purpose of this study is to investigate the influence of the porosity of wave dissipating block on the reflection and transmission coefficients through a series of hydraulic experiments where four kinds of wave dissipating blocks were used. Wave dissipating blocks with smaller porosity provided a larger reflection coefficient and a smaller transmission coefficient as a whole. However, a wave dissipating block provided a smaller reflection coefficient and a smaller transmission coefficient in spite of relatively larger porosity. The measured reflection and transmission coefficients were compared with those estimated by existing equations.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/lqyzabMw66U

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