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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

Incident, transmitted and reflected electromagnetic waves in a filled transmission line.
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pone.0140505.g001: Incident, transmitted and reflected electromagnetic waves in a filled transmission line.

Mentions: The FEM technique based COMSOL software is used to determine the exact transmission (S21) and reflection (S11) coefficients of the closed T/R rectangular waveguide. This model consists of a pair of rectangular waveguides with wave propagates in the transition between them. There are 16 boundaries; two of them for ports, another two represent the continuity on the sample surfaces while the rest are perfect electric conductors. For propagation problem, the harmonic propagation module of RF-electromagnetic waves is applied for the model. The problem is divided into three Regions: Region I (p<0), Region II (0≤p≤d) and Region III (p>d) for simpler analyses process. Fig 1 shows the waveguide excited by TE10 dominant mode and the transmission and reflection coefficients were measured at the reference plane (S1; z = 0 and S2; z = d). By utilizing the waveguide vector modal functions, the transverse electromagnetic fields in both regions I and III are explained by [17].


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)

Incident, transmitted and reflected electromagnetic waves in a filled transmission line.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0140505.g001: Incident, transmitted and reflected electromagnetic waves in a filled transmission line.
Mentions: The FEM technique based COMSOL software is used to determine the exact transmission (S21) and reflection (S11) coefficients of the closed T/R rectangular waveguide. This model consists of a pair of rectangular waveguides with wave propagates in the transition between them. There are 16 boundaries; two of them for ports, another two represent the continuity on the sample surfaces while the rest are perfect electric conductors. For propagation problem, the harmonic propagation module of RF-electromagnetic waves is applied for the model. The problem is divided into three Regions: Region I (p<0), Region II (0≤p≤d) and Region III (p>d) for simpler analyses process. Fig 1 shows the waveguide excited by TE10 dominant mode and the transmission and reflection coefficients were measured at the reference plane (S1; z = 0 and S2; z = d). By utilizing the waveguide vector modal functions, the transverse electromagnetic fields in both regions I and III are explained by [17].

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