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Theoretical and Numerical Approaches for Determining the Reflection and Transmission Coefficients of OPEFB-PCL Composites at X-Band Frequencies.

Ahmad AF, Abbas Z, Obaiys SJ, Ibrahim N, Hashim M, Khaleel H - PLoS ONE (2015)

Bottom Line: In contrast to the effective medium theory, which states that polymer-based composites with a high dielectric constant can be obtained by doping a filler with a high dielectric constant into a host material with a low dielectric constant, this paper demonstrates that the use of a low filler percentage (12.2%OPEFB) and a high matrix percentage (87.8%PCL) provides excellent results for the dielectric constant and loss factor, whereas 63.8% filler material with 36.2% host material results in lower values for both the dielectric constant and loss factor.The comparative approach indicates that the mean relative error of FEM is smaller than that of NRW in terms of the corresponding S21 magnitude.The present calculation of the matrix/filler percentages endorses the exact amounts of substrate utilized in various physics applications.

View Article: PubMed Central - PubMed

Affiliation: Institute for Mathematical Research, Universiti Putra Malaysia, Serdang, Selangor Darul Ehsan, Malaysia.

ABSTRACT
Bio-composites of oil palm empty fruit bunch (OPEFB) fibres and polycaprolactones (PCL) with a thickness of 1 mm were prepared and characterized. The composites produced from these materials are low in density, inexpensive, environmentally friendly, and possess good dielectric characteristics. The magnitudes of the reflection and transmission coefficients of OPEFB fibre-reinforced PCL composites with different percentages of filler were measured using a rectangular waveguide in conjunction with a microwave vector network analyzer (VNA) in the X-band frequency range. In contrast to the effective medium theory, which states that polymer-based composites with a high dielectric constant can be obtained by doping a filler with a high dielectric constant into a host material with a low dielectric constant, this paper demonstrates that the use of a low filler percentage (12.2%OPEFB) and a high matrix percentage (87.8%PCL) provides excellent results for the dielectric constant and loss factor, whereas 63.8% filler material with 36.2% host material results in lower values for both the dielectric constant and loss factor. The open-ended probe technique (OEC), connected with the Agilent vector network analyzer (VNA), is used to determine the dielectric properties of the materials under investigation. The comparative approach indicates that the mean relative error of FEM is smaller than that of NRW in terms of the corresponding S21 magnitude. The present calculation of the matrix/filler percentages endorses the exact amounts of substrate utilized in various physics applications.

No MeSH data available.


Related in: MedlinePlus

(a) Waveguide mesh carrying material sample (b) Electric field of a waveguide carrying sample.
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pone.0140505.g002: (a) Waveguide mesh carrying material sample (b) Electric field of a waveguide carrying sample.

Mentions: Where μr is the complex permeability, Ko is the free space wave number, j is an imaginary unit, δ is the conductivity, ω is the angular frequency, εr is the relative permittivity, and εo is the permittivity of free space. The tetrahedron is used to describe the waveguide space because of its versatility in being able to conform for many other shapes. A fine mesh approximation type is accomplished due to its best accuracy for the waveguide carrying material sample. The mesh composed of triangles is generated from the cross-section of the waveguides, which is drawn in two dimensions with the aligned material sample. These triangles increase as the electrical density of the material sample increases. Subsequently, the 2D mesh is extruded into the depth dimension with a finite number of layers, producing triangular prism elements that divide into tetrahedrons, which generate the three-dimensional waveguide. Fig 2a shows the waveguide mesh with the material sample. The unknown field within each tetrahedron can be interpolated from each node value by a first-order polynomial. Fig 2b shows the normal electric distribution for an interpolated sample placed inside a waveguide of frequencies in the range of 8-12GHz. This figure shows that the electric field decreases as the excitation passes through the sample.


Theoretical and Numerical Approaches for Determining the Reflection and Transmission Coefficients of OPEFB-PCL Composites at X-Band Frequencies.

Ahmad AF, Abbas Z, Obaiys SJ, Ibrahim N, Hashim M, Khaleel H - PLoS ONE (2015)

(a) Waveguide mesh carrying material sample (b) Electric field of a waveguide carrying sample.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4608678&req=5

pone.0140505.g002: (a) Waveguide mesh carrying material sample (b) Electric field of a waveguide carrying sample.
Mentions: Where μr is the complex permeability, Ko is the free space wave number, j is an imaginary unit, δ is the conductivity, ω is the angular frequency, εr is the relative permittivity, and εo is the permittivity of free space. The tetrahedron is used to describe the waveguide space because of its versatility in being able to conform for many other shapes. A fine mesh approximation type is accomplished due to its best accuracy for the waveguide carrying material sample. The mesh composed of triangles is generated from the cross-section of the waveguides, which is drawn in two dimensions with the aligned material sample. These triangles increase as the electrical density of the material sample increases. Subsequently, the 2D mesh is extruded into the depth dimension with a finite number of layers, producing triangular prism elements that divide into tetrahedrons, which generate the three-dimensional waveguide. Fig 2a shows the waveguide mesh with the material sample. The unknown field within each tetrahedron can be interpolated from each node value by a first-order polynomial. Fig 2b shows the normal electric distribution for an interpolated sample placed inside a waveguide of frequencies in the range of 8-12GHz. This figure shows that the electric field decreases as the excitation passes through the sample.

Bottom Line: In contrast to the effective medium theory, which states that polymer-based composites with a high dielectric constant can be obtained by doping a filler with a high dielectric constant into a host material with a low dielectric constant, this paper demonstrates that the use of a low filler percentage (12.2%OPEFB) and a high matrix percentage (87.8%PCL) provides excellent results for the dielectric constant and loss factor, whereas 63.8% filler material with 36.2% host material results in lower values for both the dielectric constant and loss factor.The comparative approach indicates that the mean relative error of FEM is smaller than that of NRW in terms of the corresponding S21 magnitude.The present calculation of the matrix/filler percentages endorses the exact amounts of substrate utilized in various physics applications.

View Article: PubMed Central - PubMed

Affiliation: Institute for Mathematical Research, Universiti Putra Malaysia, Serdang, Selangor Darul Ehsan, Malaysia.

ABSTRACT
Bio-composites of oil palm empty fruit bunch (OPEFB) fibres and polycaprolactones (PCL) with a thickness of 1 mm were prepared and characterized. The composites produced from these materials are low in density, inexpensive, environmentally friendly, and possess good dielectric characteristics. The magnitudes of the reflection and transmission coefficients of OPEFB fibre-reinforced PCL composites with different percentages of filler were measured using a rectangular waveguide in conjunction with a microwave vector network analyzer (VNA) in the X-band frequency range. In contrast to the effective medium theory, which states that polymer-based composites with a high dielectric constant can be obtained by doping a filler with a high dielectric constant into a host material with a low dielectric constant, this paper demonstrates that the use of a low filler percentage (12.2%OPEFB) and a high matrix percentage (87.8%PCL) provides excellent results for the dielectric constant and loss factor, whereas 63.8% filler material with 36.2% host material results in lower values for both the dielectric constant and loss factor. The open-ended probe technique (OEC), connected with the Agilent vector network analyzer (VNA), is used to determine the dielectric properties of the materials under investigation. The comparative approach indicates that the mean relative error of FEM is smaller than that of NRW in terms of the corresponding S21 magnitude. The present calculation of the matrix/filler percentages endorses the exact amounts of substrate utilized in various physics applications.

No MeSH data available.


Related in: MedlinePlus