scholarly journals Preparation and Thickness Optimization of Graphenic-Based Carbon Material as a Microwave Absorber

2022 ◽  
Vol 19 (1) ◽  
pp. 1714
Author(s):  
Affandi Faisal Kurniawan ◽  
Mohammad Syaiful Anwar ◽  
Khoirotun Nadiyyah ◽  
Yana Taryana ◽  
Muhammad Mahyiddin Ramli ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Layer Thickness ◽  
Reflection Loss ◽  
Morphological Structure ◽  
Single Layer ◽  
Functional Materials ◽  
Microwave Absorber ◽  
Coconut Shell ◽  
Complex Permeability ◽  
Carbon Compounds

The purpose of this study is to optimize the thickness of a layered graphenic-based carbon compound, which is a non-magnetic material derived from biomass (old coconut shell). After the sample was exfoliated using HCl solution, the morphological structure showed that the material used in this study is a reduced graphene oxide (rGO), similar to carbon but with a thickness of less than 10 nm and lateral size in submicron (100 nm). The sample with a 2 mm thickness was then characterized using a vector network analyzer (VNA) to measure its reflection loss (RL). The measurement result is evaluated by converting the S-parameter values (S11 and S21) from the VNA using the Nicolsson Ross Weir (NRW) method to obtain input variables such as relative complex permeability and relative complex permittivity. Following this, the single-layer thickness of the sample was optimized using a genetic algorithm (GA), which can predict the appropriate thickness so that the optimum RL can be obtained. The optimum thickness of the sample was found to be 3.48 mm, which resulted in a much higher RL. The RL was re-measured for verification using a sample with the corresponding optimized thickness, revealing that this optimization is feasibly operational for a radar absorbing material (RAM) design. HIGHLIGHTS Carbon compounds containing graphenic phase derived from coconut shell are functional materials having various unique properties such as superior electrical conductivity, large surface area, and excellent structural flexibility, and microwave absorbtion The single-layer microwave absorber employing carbon compounds has been prepared The layer thickness optimized using a genetic algorithm (GA) can estimate the appropriate design with the maximum reflection loss (RL)

Basic Characteristics of the Single Layer Type Microwave Absorber in X Band Using Superconductor Powder

2006 ◽  
Vol 47 ◽  
pp. 93-97
Author(s):  
Katsuyoshi Hotta ◽  
Hiroyuki Shimizu ◽  
Y. Watanabe ◽  
Haruo Hirose
Keyword(s):  
Reflection Loss ◽  
Short Circuit ◽  
Single Layer ◽  
Liquid Nitrogen Temperature ◽  
Microwave Absorber ◽  
Complex Permeability ◽  
Theoretical Formula ◽  
X Band ◽  
Guide System ◽  
Basic Characteristics

The purpose of this study is to examine the basic characteristics of the single layer type microwave absorber in X band. Samples were produced from Bi system (2223) superconductor powder and metallic powder and inserted into a wave guide system where the complex reflection intensity was measured (The short circuit method) by using the vector network analyzer[1]. As the result, at the room temperature (300K), the reflection loss is apt to increase with increasing the content of the Bi system superconductor powder. Furthermore, the measured value of the reflection loss agreed with the value calculated from the complex permittivity εr* . At liquid nitrogen temperature (77K) where the superconductor powders are in the superconducting state, some differences occurred between the calculated value and the measured one of the reflection loss. For the metallic powders, copper powder showed good agreement between the calculated and the measured of reflection loss. For the magnetic material, it was concluded that the theoretical formula under consideration of complex permeability μr* should be derivated.

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.

Making Graphene-type Material via Polymerization of Porphyrin

2020 ◽  
Author(s):  
SANJIB KAR ◽  
Sruti Mondal ◽  
Kasturi Sahu ◽  
Dilruba Hasina ◽  
Tapobrata Som ◽  
...  
Keyword(s):  
Layer Thickness ◽  
Polymeric Material ◽  
Single Layer ◽  
Type Material ◽  
Synthetic Pathway ◽  
Simple Chemical ◽  
Doped Graphene ◽  
Ring Nitrogen ◽  
2D Structure ◽  
Porphyrin Macrocycles

<p>The synthesis of new graphene-type materials (<i>via</i> polymerization of porphyrin macrocycles) through a simple chemical synthetic pathway (at RT) has been demonstrated. This newly synthesized material can be dispersed in water with an average sheet size of few microns and with single layer thickness. As the porphyrin contains four inner ring nitrogen atoms thus the presented polymeric material will be close analogous of N-doped graphene. Porphyrin as the key component to synthesize layered graphene type continuous 2D structure has never been attempted before. </p> <p> </p>

Phenomenological and Structural Aspects of the Mechanical Response of Arteries

2000 ◽  
Author(s):  
Ray W. Ogden ◽  
Christian A. J. Schulze-Bauer
Keyword(s):  
Residual Stresses ◽  
Mechanical Response ◽  
Physiological State ◽  
Circumferential Stress ◽  
Morphological Structure ◽  
Cylindrical Tube ◽  
Single Layer ◽  
Theory Of Elasticity ◽  
Starting Point ◽  
Circular Cylindrical Tube

Abstract In this paper we present some new data from extension-inflation tests on a human iliac artery and then, on the basis of the nonlinear theory of elasticity, we examine a possible model to represent this data. The model considers the artery initially as a thick-walled circular cylindrical tube which may consist of two or more concentric layers. In order to take some account of the architecture (morphological structure), each layer of the material is regarded as consisting of two families of mechanically equivalent helical fibers symmetrically disposed with respect to the cylinder axis. The resulting material properties are then orthotropic in each layer. General formulas for the pressure and the axial load in the symmetric inflation of an extended tube are obtained. The starting point is the unloaded circular cylindrical configuration, but (in general unknown) residual stresses are included in the formulation. The model is illustrated by specializing firstly to the case of a single layer so that the consequences of the hypothesis of uniform circumferential stress in the physiological state can be examined theoretically. This enables the required residual stresses to be calculated explicitly. Secondly, the equations are specialized for the membrane approximation in order to show how certain important characteristics of the experimental data can be replicated using a relatively simple anisotropic membrane model.

The sp2 character of new two-dimensional AsB with tunable electronic properties predicted by theoretical studies

2019 ◽  
Vol 21 (37) ◽  
pp. 20981-20987
Author(s):  
Jie Zhang ◽  
Huijun Liu ◽  
Yun Gao ◽  
Xiaohong Xia ◽  
Zhongbing Huang
Keyword(s):  
Electronic Material ◽  
Electronic Properties ◽  
Layer Thickness ◽  
Single Layer ◽  
Theoretical Studies ◽  
Two Dimensional ◽  
Direct Bandgap ◽  
Stacking Order ◽  
Orbital Hybridization

We identify a semiconducting 2D electronic material, single-layer AsB, which has a suitable direct bandgap of 1.18 eV. Its frontiers state is sp2 orbital hybridization, which can be effectively tuned by layer thickness, stacking order and strain.

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