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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

Measured, simulated and calculated S11 and S21 of (54.7%OPEFB+45.3%PCL).
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pone.0140505.g012: Measured, simulated and calculated S11 and S21 of (54.7%OPEFB+45.3%PCL).

Mentions: Close inspection of Figs 8–12 reveals that both S11 and S21 obtained from FEM do not show increasing or decreasing pattern with increasing OPEFB concentration. In Figs 8–11, S21 values obtained from NRW and FEM are higher than measurements while in Fig 12, S21 value obtained from FEM is lower than measurements. Similar inconsistencies for S11 are also observed when comparing calculated values and measurements. These inconsistencies can be explained by looking at FEM Eqs (3)–(13) which show that both S11 and S21 are influences by ε' and ε'' values. In NRW formulations, the parameter T is also a function of ε' and ε'' values which is not shown in Eq 18 but can be found in [23]. As shown in Table 1, ε' and ε'' values change with increasing OPEFB concentration which lead to inconsistent trend of calculated S11 and S21.


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)

Measured, simulated and calculated S11 and S21 of (54.7%OPEFB+45.3%PCL).
© Copyright Policy
Related In: Results  -  Collection

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

pone.0140505.g012: Measured, simulated and calculated S11 and S21 of (54.7%OPEFB+45.3%PCL).
Mentions: Close inspection of Figs 8–12 reveals that both S11 and S21 obtained from FEM do not show increasing or decreasing pattern with increasing OPEFB concentration. In Figs 8–11, S21 values obtained from NRW and FEM are higher than measurements while in Fig 12, S21 value obtained from FEM is lower than measurements. Similar inconsistencies for S11 are also observed when comparing calculated values and measurements. These inconsistencies can be explained by looking at FEM Eqs (3)–(13) which show that both S11 and S21 are influences by ε' and ε'' values. In NRW formulations, the parameter T is also a function of ε' and ε'' values which is not shown in Eq 18 but can be found in [23]. As shown in Table 1, ε' and ε'' values change with increasing OPEFB concentration which lead to inconsistent trend of calculated S11 and S21.

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