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Author

Taha A. Elwi

Bio: Taha A. Elwi is an academic researcher from University of Arkansas at Little Rock. The author has contributed to research in topics: Microstrip antenna & Antenna (radio). The author has an hindex of 17, co-authored 59 publications receiving 672 citations. Previous affiliations of Taha A. Elwi include Universiti Putra Malaysia & University of Baghdad.


Papers
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Journal ArticleDOI
TL;DR: A novel application that utilizes conductive patches composed of purified multi-walled carbon nanotubes embedded in a sodium cholate composite thin film to create microstrip antennas operating in the microwave frequency regime demonstrates a 5.6% to 2.2% increase in bandwidth, without significant degradation in gain and/or far-field radiation patterns.
Abstract: A novel application that utilizes conductive patches composed of purified multi-walled carbon nanotubes (MWCNTs) embedded in a sodium cholate composite thin film to create microstrip antennas operating in the microwave frequency regime is proposed. The MWCNTs are suspended in an adhesive solvent to form a conductive ink that is printed on flexible polymer substrates. The DC conductivity of the printed patches was measured by the four probe technique and the complex relative permittivity was measured by an Agilent E5071B probe. The commercial software package, CST Microwave Studio (MWS), was used to simulate the proposed antennas based on the measured constitutive parameters. An excellent agreement of less than 0.2% difference in resonant frequency is shown. Simulated and measured results were also compared against identical microstrip antennas that utilize copper conducting patches. The proposed MWCNT-based antennas demonstrate a 5.6% to 2.2% increase in bandwidth, with respect to their corresponding copper-based prototypes, without significant degradation in gain and/or far-field radiation patterns.

61 citations

Journal ArticleDOI
TL;DR: In this article, an intensive study is proposed to recycle the organic materials use for microwave applications including RF-energy harvesting, where the main texture of fabricated substrates is IPTR mixed with Nickel Oxide Nanoparticles (NONP) hosted in Polyethylene (PE) to be called INP substrates.
Abstract: In this paper, an intensive study is proposed to recycle the organic materials use for microwave applications including RF-energy harvesting. Thus, the Iraqi Palme Tree Remnants (IPTR) is exemplified for this study to create dielectric substrates. The main texture of the fabricated substrates is IPTR mixed with Nickel Oxide Nanoparticles (NONP) hosted in Polyethylene (PE) to be called INP substrates. Nevertheless, a metamaterial (MTM) printed antenna on the proposed substrate is fabricated by material printer with Sliver Nanoparticles Conductive Ink (SNPCI). The antenna performance is tested numerically/experimentally in terms of S11 spectrum and radiation patterns. It is found excellent matching bandwidths at 2.45 GHz and 5.8 GHz frequencies with acceptable gains of 1.56 dBi and 2.48 dBi, respectively. The proposed antenna bandwidth is found to start from 2.4 GHz up to more than 10 GHz. The maximum achieved gain and efficiency are found about 3.456 dBi and 78% at 9 GHz. For this, the proposed antenna provides novel performance with ultimate antenna size reduction due to the introduction of the MTM based the proposed INP substrate. Finally, the harvested RF energy by the fabricated antenna is measured and found about 15 mV with a conversation efficiency of 85% at 2.45 GHz and 17.5 mV with a conversion efficiency of 91% at 5.8 GHz.

52 citations

Journal ArticleDOI
TL;DR: A novel cylindrical antenna array of a miniaturized structure is introduced for multi input multi output systems and exhibits a gain of 2.5 dBi with broad side radiation patterns with excellent agreement between the measured and simulated results.
Abstract: In this paper, a novel cylindrical antenna array of a miniaturized structure is introduced for multi input multi output systems. The antenna array is consistent of four omega-shaped monopoles folded on a flexible cylindrical substrate of Kodak photo papers. The cylinder height is fixed to λo/4.5 with a diameter of λo/3.5, where λo is the free space wavelength at 2.25 GHz, with a separation distance between monopole elements of λo/29. The maximum mutual coupling between the monopoles elements over the frequency range from 2 to 3 GHz is found about −30 dB at the resonant frequency. Such coupling reduction is achieved by mounting conformal Spit Ring Resonators between the monopoles and backed by an electromagnetic band gap structure. An Ink-jet deposition process is used to print the array structure with sliver nano-particles on the substrate. Experimentally, S 11 spectrum is measured as well as the radiation patterns on both E- and H-plans at 2.25 GHz. It is found, the proposed array exhibits a gain of 2.5 dBi with broad side radiation patterns. An excellent agreement is achieved between the measured and simulated results.

50 citations

Journal ArticleDOI
TL;DR: In this paper, a cylindrical antenna of a miniaturized printed circuitry is invented for Microwave Radiology Imaging (MRI) applications, where a folded metamaterial structure based a Frequency Selective Surface (FSS) on a cylinrical profile is conducted in the design methodology.

44 citations


Cited by
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Journal ArticleDOI
TL;DR: Being the most conductive, as well as water-dispersible, among solution-processed 2D materials, MXenes open new avenues for manufacturing various classes of RF and other portable, flexible, and wearable electronic devices.
Abstract: With the development of the Internet of Things (IoT), the demand for thin and wearable electronic devices is growing quickly The essential part of the IoT is communication between devices, which requires radio-frequency (RF) antennas Metals are widely used for antennas; however, their bulkiness limits the fabrication of thin, lightweight, and flexible antennas Recently, nanomaterials such as graphene, carbon nanotubes, and conductive polymers came into play However, poor conductivity limits their use We show RF devices for wireless communication based on metallic two-dimensional (2D) titanium carbide (MXene) prepared by a single-step spray coating We fabricated a ~100-nm-thick translucent MXene antenna with a reflection coefficient of less than −10 dB By increasing the antenna thickness to 8 μm, we achieved a reflection coefficient of −65 dB We also fabricated a 1-μm-thick MXene RF identification device tag reaching a reading distance of 8 m at 860 MHz Our finding shows that 2D titanium carbide MXene operates below the skin depth of copper or other metals as well as offers an opportunity to produce transparent antennas Being the most conductive, as well as water-dispersible, among solution-processed 2D materials, MXenes open new avenues for manufacturing various classes of RF and other portable, flexible, and wearable electronic devices

333 citations

Journal ArticleDOI
02 Dec 2010-Sensors
TL;DR: Recent progress in non-invasive monitoring technologies for chronic disease management is reviewed and devices and techniques for monitoring blood pressure, blood glucose levels, cardiac activity and respiratory activity are discussed; in addition, on-body propagation issues for multiple sensors are presented.
Abstract: The emergence of wireless technologies and advancements in on-body sensor design can enable change in the conventional health-care system, replacing it with wearable health-care systems, centred on the individual. Wearable monitoring systems can provide continuous physiological data, as well as better information regarding the general health of individuals. Thus, such vital-sign monitoring systems will reduce health-care costs by disease prevention and enhance the quality of life with disease management. In this paper, recent progress in non-invasive monitoring technologies for chronic disease management is reviewed. In particular, devices and techniques for monitoring blood pressure, blood glucose levels, cardiac activity and respiratory activity are discussed; in addition, on-body propagation issues for multiple sensors are presented.

330 citations

Journal ArticleDOI
01 Apr 2018-Carbon
TL;DR: In this paper, a flexible graphite film was designed and explored to create dipole antennas for radio frequency applications, which achieved a relatively high peak gain of 1.45 dB with comparable return loss, bandwidth, and radiation patterns to an identical copper antenna.

99 citations

Journal ArticleDOI
TL;DR: In this paper, a new kind of metamaterial (MTM) absorber was proposed for the solar cell applications, which is particularly presented in a range of the solar spectrum in order to utilize the solar energy efficiently.
Abstract: We design, characterize, and analyze a new kind of metamaterial (MTM) absorber (MA) in difierent frequency regions for the solar cell applications. This MTM based structure is particularly presented in a range of the solar spectrum in order to utilize the solar energy efiectively. The proposed MTM based solar cell provides perfect absorption for both infrared and visible frequency ranges and can be used for the realization of more e-cient new solar cells. The structure is also tested in terms of the polarization angle independency. The suggested MA has a simple conflguration which introduces ∞exibility to adjust its MTM properties to be used in solar cells and can easily be re-scaled for other frequency ranges. Our experimental results in microwave frequencies conflrm the perfect absorption for the resonance frequency and agree with the simulation results. This means that the developed MA for solar cells will ofier perfect absorption in infrared and even in visible frequencies.

97 citations