scholarly journals Electromagnetic response from multilayer composite coatings based on carbonyl iron, ferroelectrics and MWCNTs at microwave

2019 ◽  
Vol 30 ◽  
pp. 07011
Author(s):  
Grigoriy E. Kuleshov ◽  
Alexey V. Sbrodov ◽  
Tatyana N. Shematilo
Keyword(s):  
Experimental Study ◽  
Composite Materials ◽  
Carbonyl Iron ◽  
Composite Coatings ◽  
Dielectric Constants ◽  
Electromagnetic Response ◽  
Multilayer Composite ◽  
Frequency Range ◽  
Electromagnetic Characteristics ◽  
Frequency Dependences

The electromagnetic characteristics of composite materials based on carbonyl iron, ferroelectrics, and MWCNTs were studied in this article. The complex magnetic and dielectric constants of the experimental samples were measured in the frequency range from 1 GHz to 18 GHz. The results of calculation and the experimental study of the frequency dependences of the reflection coefficient on a multilayer composite coating located on a reflective surface are presented.

scholarly journals Electromagnetic characteristics of filaments for 3D printing with carbon fillers in the microwave range

2019 ◽  
Vol 30 ◽  
pp. 07010
Author(s):  
Grigoriy E. Kuleshov ◽  
Alexander V. Badin ◽  
Kirill V. Bilinsky ◽  
Kirill V. Dorozhkin
Keyword(s):  
Composite Materials ◽  
3D Printing ◽  
Complex Permittivity ◽  
Electromagnetic Response ◽  
Microwave Range ◽  
Additive Technology ◽  
New Radio ◽  
Electromagnetic Characteristics ◽  
Carbon Fillers ◽  
Conductive Plastics

The results of a study of the complex permittivity and electromagnetic response from polymer composite materials obtained by additive technology from 3D printing filaments containing various carbon fillers are presented. New radio filaments for 3D printing with MWCNTs have been created. Investigated PLA-Conductive plastics may be used to create a shielding coating or narrowband absorbers for microwave range.

Observation of Dielectric Peaks in Glassy Se70Te20Sn10 Alloy

2012 ◽  
Vol 329 ◽  
pp. 165-175 ◽  
Author(s):  
A. Sharma ◽  
N. Mehta
Keyword(s):  
Chalcogenide Glasses ◽  
Relaxation Times ◽  
Dielectric Dispersion ◽  
Dielectric Constants ◽  
Audio Frequency ◽  
Frequency Range ◽  
Glass Transition Region ◽  
Dipolar Relaxation ◽  
The Past ◽  
Frequency Dependences

The Temperature and Frequency Dependences of the Dielectric Constants () and Dielectric Loss (") Were Studied in Glassy Se70Te20Sn10Alloy in the Audio-Frequency Range below the Glass Transition Region. the Results Indicated that Dielectric Dispersion Occurred in Glassy Se70Te20Sn10Alloy. Well-Defined Dielectric Peaks Were Obtained in Glassy Se70Te20Sn10Alloy; these Are Rarely Observed in Chalcogenide Glasses. such Loss Peaks Were Not Observed in the Glassy Se80-xTe20SnxSystem in the past for Sn Concentrations of x ≤ 8. A Detailed Analysis of the Data Showed that the Results Could Be Explained in Terms of Dipolar Relaxation, with a Distribution of Relaxation Times, this Is Quite Expected in the Case of Chalcogenide Glasses.

scholarly journals Electromagnetic response from composite carbon-containing structures with technological inhomogeneities at EHF

2021 ◽  
Vol 2140 (1) ◽  
pp. 012010
Author(s):  
E A Trofimov ◽  
G E Kuleshov ◽  
V D Moskalenko ◽  
A V Badin ◽  
K V Dorozhkin
Keyword(s):  
3D Printing ◽  
Transmission Coefficient ◽  
Composite Structures ◽  
Electromagnetic Response ◽  
Frequency Range ◽  
Absorption Coefficients ◽  
Polymer Volume ◽  
Composite Carbon ◽  
Frequency Dependences

Abstract The results of studies of the electromagnetic response from composite structures made of a carbon-containing polymer with the inclusion of spherical pores in the bulk of the material and with pyramidal corrugation on the surface of the material are presented. The results of modeling the frequency dependences of the transmission, reflection and absorption coefficients in the EHF range are shown. Samples of composite carbon-containing structures with technological inhomogeneities have been fabricated by 3D printing. Measurements of the electromagnetic response from experimental samples were carried out in the frequency range from 100 to 1000 GHz. At frequencies up to 250 GHz, the inclusion of air pores in the polymer volume reduces the transmission coefficient, practically does not affect the reflection, and increases the absorption. Pyramid corrugated material absorbs more than 99% of radiation in the frequency range from 200 to 635 GHz.

scholarly journals Electromagnetic characteristics of materials based on ultrafine hexaferrite powders

2021 ◽  
Vol 1198 (1) ◽  
pp. 012005
Author(s):  
YuN Gladkov ◽  
AS Kachalov ◽  
EYu Korovyn ◽  
AA Pavlova
Keyword(s):  
Composite Materials ◽  
Dielectric Permittivity ◽  
Frequency Dependence ◽  
Mechanical Treatment ◽  
Wide Band ◽  
Vector Network Analyzer ◽  
Network Analyzer ◽  
Frequency Range ◽  
Nanosized Powders ◽  
Electromagnetic Characteristics

Abstract The electromagnetic characteristics of composite materials based on nanosized powders of W-type hexaferrites are considered in the article. It is shown that not only the composition, but also the mechanical treatment affects the electromagnetic parameters. This article presents the frequency dependence of the complex magnetic and dielectric permittivity of a system of W-type hexafferites. The studies were carried out on a universal wide-band measuring complex based on the Agilent PNA-X N4257A Vector Network Analyzer. The results are presented in the frequency range from 2 to 14 GHz.

Carbonyl Iron/Graphite Double-Layer Structural Absorbing Composite

2012 ◽  
Vol 557-559 ◽  
pp. 390-393
Author(s):  
Jing Lan Deng ◽  
Bing Feng
Keyword(s):  
Composite Materials ◽  
Carbonyl Iron ◽  
Impedance Matching ◽  
Resin Matrix ◽  
Frequency Range ◽  
Matching Layer ◽  
Peak Absorption ◽  
Absorbing Material ◽  
Absorbing Layer ◽  
Stealth Materials

A study of a new structured composite absorbing material, prepared using carbonyl iron and graphite as absorbers within a resin matrix. The study investigated the effects of varying the concentration of absorbing agent within the layers of the absorbing composite. Results show that the best absorbency was achieved when the impedance-matching layer contained 20% carbonyl iron content and the absorbing layer contained 35% graphite. The peak absorption was -20.19 dB, with a bandwidth of 7.3GHz (R< -10 dB) in the frequency range of 8 to 18 GHz. This work will certainly have significance guiding research on the application of stealth materials and composite materials.

scholarly journals Impedance Spectroscopy of Lead-Free Ferroelectric Coatings

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 221
Author(s):  
Mariya Aleksandrova ◽  
Ivailo Pandiev
Keyword(s):  
Composite Coatings ◽  
Electrical Circuit ◽  
Ferroelectric Materials ◽  
Piezoelectric Transducers ◽  
Lead Free ◽  
Electrical Behavior ◽  
Oxide Composite ◽  
Before And After ◽  
Frequency Dependences ◽  
Good Agreement

This paper presents impedance measurements of ferroelectric structures involving lead-free oxide and polymer-oxide composite coatings for sensing and energy harvesting applications. Three different ferroelectric materials grown by conventional microfabrication technologies on solid or flexible substrates are investigated for their basic resonant characteristics. Equivalent electrical circuit models are applied to all cases to explain the electrical behavior of the structures, according to the materials type and thickness. The analytical results show good agreement with the experiments carried out on a basic types of excited thin-film piezoelectric transducers. Additionally, temperature and frequency dependences of the dielectric permittivity and losses are measured for the polymer-oxide composite device in relation with the surface morphology before and after introduction of the polymer to the functional film.

scholarly journals A hybrid broadband metalens operating at ultraviolet frequencies

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Farhan Ali ◽  
Serap Aksu
Keyword(s):  
Dielectric Material ◽  
Berry Phase ◽  
Uv Light ◽  
Fdtd Method ◽  
Numerical Aperture ◽  
Limited Range ◽  
Unit Cell ◽  
Dielectric Constants ◽  
Phase Method ◽  
Frequency Range

AbstractThe investigation on metalenses have been rapidly developing, aiming to bring compact optical devices with superior properties to the market. Realizing miniature optics at the UV frequency range in particular has been challenging as the available transparent materials have limited range of dielectric constants. In this work we introduce a low absorption loss and low refractive index dielectric material magnesium oxide, MgO, as an ideal candidate for metalenses operating at UV frequencies. We theoretically investigate metalens designs capable of efficient focusing over a broad UV frequency range (200–400 nm). The presented metalenses are composed of sub-wavelength MgO nanoblocks, and characterized according to the geometric Pancharatnam–Berry phase method using FDTD method. The presented broadband metalenses can focus the incident UV light on tight focal spots (182 nm) with high numerical aperture ($$\hbox {NA}\approx 0.8$$ NA ≈ 0.8 ). The polarization conversion efficiency of the metalens unit cell and focusing efficiency of the total metalens are calculated to be as high as 94%, the best value reported in UV range so far. In addition, the metalens unit cell can be hybridized to enable lensing at multiple polarization states. The presented highly efficient MgO metalenses can play a vital role in the development of UV nanophotonic systems and could pave the way towards the world of miniaturization.

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