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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

S-parameter measurement processes.
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pone.0140505.g004: S-parameter measurement processes.

Mentions: The network analyzer was calibrated using the standard full two-port Electronic calibration method (ECAL). The S-parameters measurements were carried out using closed T/R rectangular waveguide connected with two ports VNA as is clear in Fig 4. As recommended by the manufacturer, ECAL technique was applied to eliminate the systematic errors in S21and S11 measurements. The samples were cut to fit snugly into the rectangular waveguide. Fig 4 shows the measurements setup as well as the fitted sample inside the waveguide. Three different places of the obtained slab with same composition were measured to make sure the homogeneity of the prepared composites. The dielectric properties (ε′ and ε′′) of the samples were measured using an OEC connected with a VNA via a cable, where the probe was placed on the flat surface of the samples without an air gap. The measurement method was based on the input reflection coefficient of the coaxial line against the samples. The measurements of the ε′ and ε′′ of the samples were performed in room temperature at X-band frequency. The relative permittivity results obtained from the OEC are then used by the FEM technique for the simulation and subsequent calculation of the S-parameters of the samples used in this study. The S-parameter results obtained using the rectangular waveguide technique and the FEM were compared with those obtained using the NRW method.


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)

S-parameter measurement processes.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0140505.g004: S-parameter measurement processes.
Mentions: The network analyzer was calibrated using the standard full two-port Electronic calibration method (ECAL). The S-parameters measurements were carried out using closed T/R rectangular waveguide connected with two ports VNA as is clear in Fig 4. As recommended by the manufacturer, ECAL technique was applied to eliminate the systematic errors in S21and S11 measurements. The samples were cut to fit snugly into the rectangular waveguide. Fig 4 shows the measurements setup as well as the fitted sample inside the waveguide. Three different places of the obtained slab with same composition were measured to make sure the homogeneity of the prepared composites. The dielectric properties (ε′ and ε′′) of the samples were measured using an OEC connected with a VNA via a cable, where the probe was placed on the flat surface of the samples without an air gap. The measurement method was based on the input reflection coefficient of the coaxial line against the samples. The measurements of the ε′ and ε′′ of the samples were performed in room temperature at X-band frequency. The relative permittivity results obtained from the OEC are then used by the FEM technique for the simulation and subsequent calculation of the S-parameters of the samples used in this study. The S-parameter results obtained using the rectangular waveguide technique and the FEM were compared with those obtained using the NRW method.

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