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Highly Omnidirectional and Frequency Controllable Carbon/Polyaniline-based 2D and 3D Monopole Antenna.

Shin KY, Kim M, Lee JS, Jang J - Sci Rep (2015)

Bottom Line: Solvated C/PANI was synthesized by low-temperature interfacial polymerization, during which strong π-π interactions between graphene and the quinoid rings of PANI resulted in an expanded PANI conformation with enhanced crystallinity and improved mechanical and electrical properties.These antennas attained high peak gain (3.60 dBi), high directivity (3.91 dBi) and radiation efficiency (92.12%) relative to 2D monopole antenna.These improvements were attributed the high packing density and aspect ratios of C/PANI fibers and the removal of the flexible substrate.

View Article: PubMed Central - PubMed

Affiliation: World Class University program of Chemical Convergence for Energy &Environment, School of Chemical and Biological Engineering, Seoul National University, 151-742, Korea.

ABSTRACT
Highly omnidirectional and frequency controllable carbon/polyaniline (C/PANI)-based, two- (2D) and three-dimensional (3D) monopole antennas were fabricated using screen-printing and a one-step, dimensionally confined hydrothermal strategy, respectively. Solvated C/PANI was synthesized by low-temperature interfacial polymerization, during which strong π-π interactions between graphene and the quinoid rings of PANI resulted in an expanded PANI conformation with enhanced crystallinity and improved mechanical and electrical properties. Compared to antennas composed of pristine carbon or PANI-based 2D monopole structures, 2D monopole antennas composed of this enhanced hybrid material were highly efficient and amenable to high-frequency, omnidirectional electromagnetic waves. The mean frequency of C/PANI fiber-based 3D monopole antennas could be controlled by simply cutting and stretching the antenna. These antennas attained high peak gain (3.60 dBi), high directivity (3.91 dBi) and radiation efficiency (92.12%) relative to 2D monopole antenna. These improvements were attributed the high packing density and aspect ratios of C/PANI fibers and the removal of the flexible substrate. This approach offers a valuable and promising tool for producing highly omnidirectional and frequency-controllable, carbon-based monopole antennas for use in wireless networking communications on industrial, scientific, and medical (ISM) bands.

No MeSH data available.


(a) The measured return loss curves are given for 2D monopole antennas composed of carbon, PANI, and C/PANI-based electrodes. (b) The simulated radiation pattern of a C/PANI-based 2D monopole antenna is shown using Ansoft HFSS.
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f3: (a) The measured return loss curves are given for 2D monopole antennas composed of carbon, PANI, and C/PANI-based electrodes. (b) The simulated radiation pattern of a C/PANI-based 2D monopole antenna is shown using Ansoft HFSS.

Mentions: Based on the above analyses, three different line patterns were used to make the electrodes for 2D monopole antennas. Generally, the performance of an antenna is evaluated using its mean frequency and voltage standing wave ratio (VSWR) or return loss (RL), which is indicative of transmitted power efficiency4041. It refers to the loss of power due to impedance mismatching, which is designing the input impedance of an electrical load or the output impedance of its corresponding signal source to maximize the power transfer or minimize signal reflection from the load. Carbon, PANI, and C/PANI-based 2D monopole antennas had mean frequencies of 874.5 MHz, and 1.31 and 1.98 GHz, respectively (Fig. 3a). The VSWR (1.27) and RL (18.5) values of the C/PANI-based 2D monopole antennas indicated an increase in transmitted power efficiency of 98.6%, and the simulated values were also shown in Table 2. The large differences in mean frequency can be ascribed to differences in the permittivities of the antenna materials. In general, the speed of an electromagnetic wave propagating through a given medium is given aswhere c0,εr, and μr are the speed of light in free space, and the relative permittivity and permeability of the medium, respectively. Therefore, an increase in permittivity results in a decrease in the propagation speed of an electromagnetic wave in that medium. This then results in a decreased wavelength according towhere f and λ0 are the frequency and wavelength of a plane wave in free space, respectively. The power gain, defined as the ratio of the power produced by the antenna from a far-field source on the antenna beam axis to the power produced by a hypothetical lossless isotropic antenna, of three types of 2D monopole antennas was simulated. Power gain, a metric of performance, combines the antenna directivity and radiation efficiency. Especially, radiation efficiency indicates of the ohmic/dielectric power loss in the antenna itself, and thus it is a measure of the radiating electromagnetic energy that propagates into the surrounding space through the antenna. Figure 3b shows that the C/PANI thin films acted as omnidirectional monopole antennas with relatively low gain along the substrate direction with a resultant interruption in wave propagation. The simulated radiation properties of 2D monopole antennas made from the various materials used in this study are summarized in Table 3. Compared to the carbon thin film antennas, the C/PANI-based 2D monopole antenna exhibited a peak gain of 1.49 dBi with a higher radiation efficiency of 87.83%. This is similar to the gain of a dipole antenna. These data suggest that the stronger mechanical strength, and higher permittivity and conductivity of the C/PANI thin films resulted in 2D monopole antennas with greater efficiency, higher resonance frequencies, and omnidirectionality.


Highly Omnidirectional and Frequency Controllable Carbon/Polyaniline-based 2D and 3D Monopole Antenna.

Shin KY, Kim M, Lee JS, Jang J - Sci Rep (2015)

(a) The measured return loss curves are given for 2D monopole antennas composed of carbon, PANI, and C/PANI-based electrodes. (b) The simulated radiation pattern of a C/PANI-based 2D monopole antenna is shown using Ansoft HFSS.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4559896&req=5

f3: (a) The measured return loss curves are given for 2D monopole antennas composed of carbon, PANI, and C/PANI-based electrodes. (b) The simulated radiation pattern of a C/PANI-based 2D monopole antenna is shown using Ansoft HFSS.
Mentions: Based on the above analyses, three different line patterns were used to make the electrodes for 2D monopole antennas. Generally, the performance of an antenna is evaluated using its mean frequency and voltage standing wave ratio (VSWR) or return loss (RL), which is indicative of transmitted power efficiency4041. It refers to the loss of power due to impedance mismatching, which is designing the input impedance of an electrical load or the output impedance of its corresponding signal source to maximize the power transfer or minimize signal reflection from the load. Carbon, PANI, and C/PANI-based 2D monopole antennas had mean frequencies of 874.5 MHz, and 1.31 and 1.98 GHz, respectively (Fig. 3a). The VSWR (1.27) and RL (18.5) values of the C/PANI-based 2D monopole antennas indicated an increase in transmitted power efficiency of 98.6%, and the simulated values were also shown in Table 2. The large differences in mean frequency can be ascribed to differences in the permittivities of the antenna materials. In general, the speed of an electromagnetic wave propagating through a given medium is given aswhere c0,εr, and μr are the speed of light in free space, and the relative permittivity and permeability of the medium, respectively. Therefore, an increase in permittivity results in a decrease in the propagation speed of an electromagnetic wave in that medium. This then results in a decreased wavelength according towhere f and λ0 are the frequency and wavelength of a plane wave in free space, respectively. The power gain, defined as the ratio of the power produced by the antenna from a far-field source on the antenna beam axis to the power produced by a hypothetical lossless isotropic antenna, of three types of 2D monopole antennas was simulated. Power gain, a metric of performance, combines the antenna directivity and radiation efficiency. Especially, radiation efficiency indicates of the ohmic/dielectric power loss in the antenna itself, and thus it is a measure of the radiating electromagnetic energy that propagates into the surrounding space through the antenna. Figure 3b shows that the C/PANI thin films acted as omnidirectional monopole antennas with relatively low gain along the substrate direction with a resultant interruption in wave propagation. The simulated radiation properties of 2D monopole antennas made from the various materials used in this study are summarized in Table 3. Compared to the carbon thin film antennas, the C/PANI-based 2D monopole antenna exhibited a peak gain of 1.49 dBi with a higher radiation efficiency of 87.83%. This is similar to the gain of a dipole antenna. These data suggest that the stronger mechanical strength, and higher permittivity and conductivity of the C/PANI thin films resulted in 2D monopole antennas with greater efficiency, higher resonance frequencies, and omnidirectionality.

Bottom Line: Solvated C/PANI was synthesized by low-temperature interfacial polymerization, during which strong π-π interactions between graphene and the quinoid rings of PANI resulted in an expanded PANI conformation with enhanced crystallinity and improved mechanical and electrical properties.These antennas attained high peak gain (3.60 dBi), high directivity (3.91 dBi) and radiation efficiency (92.12%) relative to 2D monopole antenna.These improvements were attributed the high packing density and aspect ratios of C/PANI fibers and the removal of the flexible substrate.

View Article: PubMed Central - PubMed

Affiliation: World Class University program of Chemical Convergence for Energy &Environment, School of Chemical and Biological Engineering, Seoul National University, 151-742, Korea.

ABSTRACT
Highly omnidirectional and frequency controllable carbon/polyaniline (C/PANI)-based, two- (2D) and three-dimensional (3D) monopole antennas were fabricated using screen-printing and a one-step, dimensionally confined hydrothermal strategy, respectively. Solvated C/PANI was synthesized by low-temperature interfacial polymerization, during which strong π-π interactions between graphene and the quinoid rings of PANI resulted in an expanded PANI conformation with enhanced crystallinity and improved mechanical and electrical properties. Compared to antennas composed of pristine carbon or PANI-based 2D monopole structures, 2D monopole antennas composed of this enhanced hybrid material were highly efficient and amenable to high-frequency, omnidirectional electromagnetic waves. The mean frequency of C/PANI fiber-based 3D monopole antennas could be controlled by simply cutting and stretching the antenna. These antennas attained high peak gain (3.60 dBi), high directivity (3.91 dBi) and radiation efficiency (92.12%) relative to 2D monopole antenna. These improvements were attributed the high packing density and aspect ratios of C/PANI fibers and the removal of the flexible substrate. This approach offers a valuable and promising tool for producing highly omnidirectional and frequency-controllable, carbon-based monopole antennas for use in wireless networking communications on industrial, scientific, and medical (ISM) bands.

No MeSH data available.