Measurement of electromagnetic properties of absorbing materials in the aerospace industry: issues and (some) answers

1992 ◽  
Author(s):  
D.A. Luippold ◽  
K.M. Mitzner ◽  
D.S. Hunzeker ◽  
W. Hant ◽  
F.J. Murray ◽  
...  
Keyword(s):  
Aerospace Industry ◽  
Electromagnetic Properties ◽  
Absorbing Materials

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.

Electromagnetic Evaluation of Multifunctional Composites for Use in Radar Absorbing Structures

2016 ◽  
Vol 1135 ◽  
pp. 104-111 ◽  
Author(s):  
Luiza de Castro Folgueras ◽  
Mauro Angelo Alves ◽  
Mirabel C. Rezende
Keyword(s):  
Glass Fiber ◽  
Microwave Radiation ◽  
Electromagnetic Properties ◽  
Tangent Loss ◽  
Multifunctional Composites ◽  
Small Thickness ◽  
High Attenuation ◽  
Microwave Absorbing Materials ◽  
X Band ◽  
Absorbing Materials

The knowledge of how to process composite materials and combine them with radiation absorbing centers, using different components, additives and polymer matrices with suitable electromagnetic properties (dielectric constant and tangent loss), allows the production of multifunctional composites that can function as conductors or microwave absorbing materials. Thus, the purpose of this study was to process and evaluate the electromagnetic properties of multilayered multifunctional composites made with layers of glass fiber cloths or nonwoven glass fiber veils pre-impregnated with formulations based on carbon black. Electromagnetic properties of the multifunctional composites were evaluated by measuring the reflection of microwave radiation using the waveguide technique in the X-band (8.2 to 12.4 GHz). The results show that the multifunctional composites absorbed 90% to 99% of the energy of the incident microwave radiation. The high attenuation of the incident microwave radiation combined with their small thickness indicate that these multifunctional composites could be used in a number of military and civilian applications.

Manufacturing radar-absorbing composite materials by using magnetic Co-doped zinc oxide particles synthesized by Sol-Gel

2020 ◽  
Vol 54 (26) ◽  
pp. 4059-4066
Author(s):  
Hüsnügül Yilmaz Atay ◽  
Öykü İçin
Keyword(s):  
Zinc Oxide ◽  
Sol Gel ◽  
Electromagnetic Properties ◽  
X Ray Diffraction ◽  
Important Place ◽  
Stealth Technology ◽  
Absorbing Materials ◽  
Potential Applications ◽  
Co Doped

An indicator of being a strong country in today's world is that they have powerful weapons. In this sector where science is used exceedingly, the “stealth” takes an important place. Radar-absorbing materials are used in stealth technology to disguise an object from radar detection, such that it can allow a plane to be perceived as a bird. In this study, Co-doped zinc oxide reinforced styrofoam sheet composites were manufactured as radar-absorbing materials. For this purpose, Co-doped zinc–ZnO particles were synthesized via the Sol-Gel method with doping concentrations of 0%, 3%, 6%, 9%, and 12%. They were embedded in a styrofoam matrix with different loading levels to see the concentration dependence. The as-prepared powders were characterized by using X-ray diffraction and Scanning Electron Microscope-Energy Dispersive Spectroscopy. Magnetic characterization of samples was carried out using a vibrating sample magnetometer. Finally, the radar-absorbing test was applied with a network analyzer to achieve the main purpose of this research. It was concluded that Co-doped zinc oxide reinforced composites have electromagnetic properties that indicate potential applications in the radar-absorbing area.

scholarly journals Effect of different permeability on electromagnetic properties of absorbing materials

2018 ◽  
Vol 197 ◽  
pp. 02015 ◽  
Author(s):  
Riser Fahdiran ◽  
Yuliyanti Dwi Utami ◽  
Erfan Handoko
Keyword(s):  
Transmission Line ◽  
Reflection Loss ◽  
Single Layer ◽  
Electromagnetic Properties ◽  
Complex Permeability ◽  
Transmission Line Theory ◽  
Microwave Frequencies ◽  
Microwave Absorbing Properties ◽  
Absorbing Materials ◽  
Line Theory

In this study, we have simulated and investigated electromagnetic properties of six types materials using a single layer metal backed absorber model that were determined at microwave frequencies 8.2 up to12.4 GHz. The reflection loss was simulated for different thicknesses in the range of 0.85 to 1.05 mm based on the relative complex permeability and permittivity referring to transmission line theory. The optimal microwave absorbing properties was be resulted by A3 sample. The minimum RL of −23.84 dB can be obtained at 10.72 GHz with thin thickness of 0.95 mm. This method paves a new avenue to design magnetic and dielectric absorbing materials.

Facet Topography and Dislocation Structure as a Possible Source for Electrical Heterogeneity in [001] TILT Bicrystals of YBa2Cu3O7-δ

1996 ◽  
Vol 54 ◽  
pp. 338-339
Author(s):  
I-Fei Tsu ◽  
D.L. Kaiser ◽  
S.E. Babcock
Keyword(s):  
Grain Boundary ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Electromagnetic Properties ◽  
Length Scale ◽  
Density Values ◽  
Current Densities ◽  
Applied Fields ◽  
A Current

A current theme in the study of the critical current density behavior of YBa2Cu3O7-δ (YBCO) grain boundaries is that their electromagnetic properties are heterogeneous on various length scales ranging from 10s of microns to ˜ 1 Å. Recently, combined electromagnetic and TEM studies on four flux-grown bicrystals have demonstrated a direct correlation between the length scale of the boundaries’ saw-tooth facet configurations and the apparent length scale of the electrical heterogeneity. In that work, enhanced critical current densities are observed at applied fields where the facet period is commensurate with the spacing of the Abrikosov flux vortices which must be pinned if higher critical current density values are recorded. To understand the microstructural origin of the flux pinning, the grain boundary topography and grain boundary dislocation (GBD) network structure of [001] tilt YBCO bicrystals were studied by TEM and HRTEM.

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