Browsing by Author "El Atrash, Mohamed"

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All-textile inspired-folded dipole antennas for on/ off-body communications medical applications
(Alexandria University, 2022-03) Kareem, Farah R; El Atrash, Mohamed; Ibrahim, Ahmed A; Abdalla, Mahmoud Ap
Two textile-based printed inspired Folded Dipole Antennas (FDAs) are presented in this paper for health monitoring of Covid-19 infected patients. The first antenna has an overall size of 80 mm 20 mm and is mounted on the human’s chest, while the second one is backed by a 2 4 textile Artificial Magnetic Conductor (AMC) array structure and is mounted on a surgical mask that covers the human’s mouth. The first antenna is designed to work at center frequency, band- width, and gain of 2.45 GHz, 116.6 MHz and 2.45 dB, respectively. The second antenna works at 2.4 GHz with bandwidth of 76.6 MHz and gain of 2.71 dB. The SAR results equal 0.524 W/ Kg and 0.255 W/Kg at 1 g and 10 g, respectively, for the first antenna and 0.0174 W/Kg and 0.0091 W/Kg, respectively, for the second one. The previous specifications of the two antennas enable them to be utilized in wearable applications and Wi-Fi services. 2022 THE AUTHORS. Published by Elsevier BV on behalf of Faculty of Engineering, Alexandria University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).
A compact dual-band D-CRLH-based antenna with self-isolation functionality
(Cambridge University press, 2021-05) Abdalla, Mahmoud A; El Atrash, Mohamed; Abdel Aziz, Ahmed A; Abdelnaser, Mohamed I
This paper presents a compact dual-band filtering antenna without extra employing of filter structures. The antenna is designed using a planar dual-composite right/left-handed (D-CRLH) transmission line unit cell, where the filtering function is achieved through current cancellation between the D-CRLH resonators. The antenna is designed to function at 3.0 and 5.1 GHz, which can serve different WLAN applications. The antenna is a co-planar waveguide fed with a very compact size of only 30 × 16 mm2. Compared to the conventional patch antenna, the antenna size is only 17% at 3.0 GHz and 31% at 5.1 GHz. Despite the small size, the antenna preserves a good omni-directional radiation pattern at the two resonant frequencies with a measured realized gain of 2 and 2.7 dB, respectively. At the stopband in-between the two resonant bands, the reflection coefficient is almost 0 dB at 4.25 GHz and complete non-radiation is proved with a −11 dB measured realized gain. The different antenna filtering functions are verified by full-wave simulation and measurements.
A compact fully fabric I‐shaped antenna supported with textile‐based AMC for low SAR 2.45 GHz wearable applications
(John Wiley & Sons Inc, 2023-01) Youssef, Omar M; El Atrash, Mohamed; Abdallah, Mahmoud A
Introduced in this letter is a thin, flexible, compact, and fully fabric I‐shaped quarter‐wavelength antenna, where a 3 × 3 array reflector, is in the antenna rear end. In free space, the I‐shaped antenna radiates at 2.45 GHz of the Industrial, Scientific, and Medical band with simulated realized gain of 1.65 dB and 90% worth of simulated radiation efficiency. The array reflector is utilized to diminish the specific absorption rate (SAR) in human evaluation scenarios. At the operating frequency, in free space, the antenna realized gain is improved by 75% after incorporating the artificial magnetic conductor (AMC) array. Moreover, over 1 g of tissue, a SAR reduction of 99.5% is attained at 2.45 GHz. Simulation and measured S11 and radiation pattern comparisons are highlighted in this letter. Based on the accomplished outcomes, the integrated antenna, comprised of the fully fabric I‐shaped quarter‐wavelength antenna and the AMC array, might be considered for wearable applications.
Concept and analysis of a coupled split-ring resonator for wide-/dual bands, self-filtering, high out-of-band suppression and highly efficient antennas
(Cambridge University Press, 05/12/2020) Abdalla, Mahmoud A.; El Atrash, Mohamed; El-Sobky, Nour A.; Zahran, Sherif R.
An inspired metamaterial-based highly efficient monopole antenna displaying wide-/dual-band resonances along with self-filtering properties is presented. The monopole has high out-of-band suppression characteristics that lead to very close to 0 dB band-stop between the antenna dual resonant bands. The antenna operates at the two WLAN services of 2.65-3.25 and 5-7 GHz with stopband with total reflection at 4.5 GHz. The designed filtering characteristics are based on current coupling for the dual-band functions and current neutralization for the stopband function. Moreover, the proposed antenna has a very high radiation efficiency of 97 and 99% at 3 and 6 GHz, respectively. Furthermore, the proposed antenna exhibits an omni-directional radiation pattern with coplanar waveguide feed for simple integration with passive/active devices. Moreover, the antenna properties are achieved with a compact antenna size (30 × 30 mm2). With all presented results, the proposed antenna is very competitive over recent relevant antennas. In addition, a very good agreement between theoretical, full-wave simulations and measurements is achieved. © 2020 Cambridge University Press and the European Microwave Association
Dual-band all textile antenna with AMC for heartbeat monitor and pacemaker control applications
(Cambridge University press, 01/12/2021) Kareem, Farah R; El Atrash, Mohamed; Ibrahim, Ahmed A; Abdalla, Mahmoud A
Currently reading: Abstract Get access Share Cite Rights & Permissions [Opens in a new window] Abstract All textile integrated dual-band monopole antenna with an artificial magnetic conductor (AMC) is proposed. The proposed design operates at 2.4 and 5.8 GHz for wearable medical applications to monitor the heartbeat. A flexible and low-profile E- shaped CPW dual-band textile antenna is integrated with a 4 × 4 dual-band textile AMC reflector to enhance the gain and specific absorption rate (SAR). The SAR is reduced by nearly 95% at both 1 and 10 g. The design was measured on the body with a 2 mm separation. The simulated and measured results appear in high agreement in the case of with and without AMC array integration. The measurement was performed in the indoor environment and in an anechoic chamber to validate the design based on reflection coefficient and radiation pattern measurements.
Fully Fabric High Impedance Surface-Enabled Antenna for Wearable Medical Applications
(IEEE, 2021-01) Ashyap, Adel Y.I; Dahlan, S. H; Abidin, Zuhairiah Zainal; Abdul Rahim, S. K; Majid, M. H. A.; Alqadami, Abdulrahman S. M.; El Atrash, Mohamed
The compact and robust high-impedance surface (HIS) integrated with the antenna is designed to operate at a frequency of 2.45 GHz for wearable applications. They are made of highly flexible fabric material. The overall size is 45×45×2.4 mm3 which equivalent to 0.37λo×0.37λo×0.02 mm3. The value of using HIS lies in protecting the human body from harmful radiation and maintaining the performance of the antenna, which may be affected by the high conductivity of the human body. Besides, setting the antenna on the human body by itself detunes the frequency, but by adding HIS, it becomes robust and efficient for body loading and deformation. Integrated antenna with HIS demonstrates excellent performance, such as a gain of 7.47 dBi, efficiency of 71.8% and FBR of 10.8 dB. It also reduces the SAR below safety limits. The reduction is more than 95%. Therefore, the presented design was considered suitable for wearable applications. Further study was also performed to show the useful of placing antenna over HIS compared to the use of perfect electric conductor (PEC). The integrated design was also investigated with the worst case of varying the permittivity of body equivalent model which shows excellent performance in term of reflection coefficient and SAR levels. Hence, the integrated antenna with HIS is mechanically robust to human body tissue loading, and it is highly appropriate for body-worn applications.
A quad-band miniaturised compact Π-shaped CSRR-based metamaterial-inspired DG resonator antenna
(Taylor and Francis, 19/09/2021) Abdalla, Mahmoud A; Wahba, Walaa W; El Atrash, Mohamed
Proposed in this paper is a new configuration for a quad-band antenna based on using a metamaterial-inspired defected ground structure. The presented structure is introduced as a new modified metamaterial Complementary Split Ring Resonator (CSRR) with a compact electrical size. The new modified CSRR has been employed in Composite Right/Left-Handed (CRLH) transmission line config- uration for ultra-size reduction. Validation for the particle small size is introduced and the detailed analysis for the NRI characteristics has been discussed by extracting the cell constitutive parameters. Hence, a multi-band antenna is designed based on using only one cell of the proposed NRI-TL. Subsequently, a small multi-band antenna is presented for different multi-band functionalities and different radiation properties. The antenna displays quad-reso- nances at 1.78 GHz, with the typical omnidirectional radiation pattern, 3.28 GHz, 4 GHz, and 4.3 GHz, with the directive broadside radiation properties. The proposed antenna footprint is 10 × 10 cm2 , which exhibits a size reduction of up to 80% in comparison with a rectangular patch antenna operating at the lowest frequency band.
A Wearable Dual-Band Low Profile High Gain Low SAR Antenna AMC-Backed for WBAN Applications
(IEEE, 2019-10) Abdalla, Mahmoud A.; El Atrash, Mohamed; Elhennawy, Hadia M
A dual-band, low profile, high gain, and low specific absorption rate (SAR) triangular slotted monopole antenna backed with a artificial magnetic conductor (AMC) array is presented for wireless body area network (WBAN) applications. The antenna is printed on a Rogers ULTRALAM 3850 substrate, whereas the AMC array is printed on a RO3003 substrate. The design operates at 3.5 GHz, for WiMAX wireless applications, and at 5.8 GHz for the ISM Band. The proposed antenna preserved the dual-band resonance and exhibited acceptable gain and SAR at a separation of 15 mm from the human body model. To reduce such separation and achieve enhancements to gain and SAR, an AMC array was utilized. In free space, gain enhancements by 6.8 and 3.7 dBi were achieved at both frequencies, respectively. Furthermore, over a gap of 1 mm from the human body, gain enhancements by 23.3 and 13.9 dBi …
Wearable high gain low SAR antenna loaded with backed all-textile EBG for WBAN applications
(Institution of Engineering and Technology, 07/01/2020) Mohamed, Ibrahim S.; El Atrash, Mohamed; Abdalgalil, Omar; Mohamed, Ibrahim; Abdalla, Mahmoud Abdelrahman; Zahran, Sherif. R.
View references (37) A high gain, low specific absorption rate, oval-shaped monopole antenna is presented. It is backed by an all-textile 3 × 3 array of electromagnetic bandgap (EBG) unit cells. The antenna is printed on the thin Rogers ULTRALAM 3850 substrate, while the EBG array is composed of the conductive ShieledIT Super and dielectric substrate felt. The design operates at 2.45 GHz of the Industrial, Scientific, and Medical band. Due to the close distance between the extended grounds of the co-planar waveguide feeding configuration and the oval-shaped monopole antenna, current-coupling was achieved, leading to gain enhancement. However, with body-loading cases, resonance at 2.45 GHz was attained at a separation of 30 mm. By incorporating the EBG array, as an isolator, this issue was resolved. In free space and over a gap of 3 mm from the human body, gain enhancements by 2.68 and 11.54 dB were achieved at 2.45 GHz, respectively. Simulated and measured results are benchmarked. Furthermore, SAR simulation study showed reductions by 99.5%, averaged over 1 and 10 g of tissue. © The Institution of Engineering and Technology 2020