Saida Ahyoud

Bio: Saida Ahyoud is an academic researcher from Abdelmalek Essaâdi University. The author has contributed to research in topics: Antenna (radio) & Radiation pattern. The author has an hindex of 7, co-authored 28 publications receiving 115 citations.

A Review of Flexible Wearable Antenna Sensors: Design, Fabrication Methods, and Applications

Abstract: This review paper summarizes various approaches developed in the literature for antenna sensors with an emphasis on flexible solutions. The survey helps to recognize the limitations and advantages of this technology. Furthermore, it offers an overview of the main points for the development and design of flexible antenna sensors from the selection of the materials to the framing of the antenna including the different scenario applications. With regard to wearable antenna sensors deployment, a review of the textile materials that have been employed is also presented. Several examples related to human body applications of flexible antenna sensors such as the detection of NaCl and sugar solutions, blood and bodily variables such as temperature, strain, and finger postures are also presented. Future investigation directions and research challenges are proposed.

A novel ultra-wide band wearable antenna under different bending conditions for electronic-textile applications

Abstract: This paper is devoted to a novel textile ultra-wideband (UWB) antenna for wearable applications. The antenna is designed and implemented on a felt textile substrate with attractive features such as...

Multiband Planar Inverted-F Antenna with Independent Operating Bands Control for Mobile Handset Applications

Abstract: A new compact multiband PIFA (Planar Inverted-F Antenna) for mobile handset is proposed in this article. The proposed PIFA has a simple geometry with four slots integrated in the radiating patch and ground plane. The PIFA occupies a small volume of 51 × 14 × 7.2 mm3 and is placed on the top portion of mobile phone. The optimized PIFA is worked in the 790 MHz band (737–831 MHz), the 1870 MHz band (1794–1977 MHz), the 2550 MHz band (2507–2615 MHz), and the 3400 MHz band (3341–3545 MHz), to cover LTE700, LTE800, DCS1800, PCS1900, LTE1800, LTE1900, LTE2500, and WIMAX3400 bands. Each of the four operating bands can be controlled independently by the variation of a single parameter of the proposed design, with a wide control range. An omnidirectional radiation pattern to each resonant frequency is obtained with a maximum gain of 2.15 dBi at 790 MHz, 3.99 dBi at 1870 MHz, 4.57 dBi at 2550 MHz, and 6.43 dBi at 3400 MHz. The proposed PIFA is studied in the free space and in the presence of other mobile phone components such as the battery, LCD (liquid crystal display), camera, microphone, speaker, buttons, and a plastic housing. The distribution of specific absorption rate for both European and American standards for each operating band and at various distances between the antenna and the human head is also studied.

PAPR Reduction Using Fireworks Search Optimization Algorithm in MIMO-OFDM Systems

Abstract: The transceiver combination technology, of orthogonal frequency division multiplexing (OFDM) with multiple-input multiple-output (MIMO), provides a viable alternative to enhance the quality of service and simultaneously to achieve high spectral efficiency and data rate for wireless mobile communication systems. However, the high peak-to-average power ratio (PAPR) is the main concern that should be taken into consideration in the MIMO-OFDM system. Partial transmit sequences (PTSs) is a promising scheme and straightforward method, able to achieve an effective PAPR reduction performance, but it requires an exhaustive search to find the optimum phase factors, which causes high computational complexity increased with the number of subblocks. In this paper, a reduced computational complexity PTS scheme is proposed, based on a novel swarm intelligence algorithm, called fireworks algorithm (FWA). Simulation results confirmed the adequacy and the effectiveness of the proposed method which can effectively reduce the computation complexity while keeping good PAPR reduction. Moreover, it turns out from the results that the proposed PTS scheme-based FWA clearly outperforms the hottest and most important evolutionary algorithm in the literature like simulated annealing (SA), particle swarm optimization (PSO), and genetic algorithm (GA).

End-to-end design of wearable sensors

Abstract: Wearable devices provide an alternative pathway to clinical diagnostics by exploiting various physical, chemical and biological sensors to mine physiological (biophysical and/or biochemical) information in real time (preferably, continuously) and in a non-invasive or minimally invasive manner. These sensors can be worn in the form of glasses, jewellery, face masks, wristwatches, fitness bands, tattoo-like devices, bandages or other patches, and textiles. Wearables such as smartwatches have already proved their capability for the early detection and monitoring of the progression and treatment of various diseases, such as COVID-19 and Parkinson disease, through biophysical signals. Next-generation wearable sensors that enable the multimodal and/or multiplexed measurement of physical parameters and biochemical markers in real time and continuously could be a transformative technology for diagnostics, allowing for high-resolution and time-resolved historical recording of the health status of an individual. In this Review, we examine the building blocks of such wearable sensors, including the substrate materials, sensing mechanisms, power modules and decision-making units, by reflecting on the recent developments in the materials, engineering and data science of these components. Finally, we synthesize current trends in the field to provide predictions for the future trajectory of wearable sensors.

A Low Correlation and Mutual Coupling MIMO Antenna

Abstract: A new two-element multiple-input multiple-output (MIMO) antenna with low correlation and high port isolation is presented. First, two hybrid electromagnetic band gap (EBG) structures with the ability to support and stop surface wave propagation, respectively, are utilized simultaneously for achieving an extremely low envelope correlation coefficient (ECC). Then, based on studying of the ground current of the MIMO antenna with EBG structure, a new defected ground structure (DGS) is used to reduce the mutual coupling by controlling the polarization of the coupling field. The two antenna elements have an edge to edge spacing of $0.13\lambda $ where $\lambda $ is the free space wavelength at the resonant frequency. Finally, the rectangular slots are introduced to the patch to improve the cross polarization. Experimental results show that the ECC of the MIMO antenna is lower than 0.002. Furthermore, the maximum mutual coupling (MC) reduction of 22dB can be achieved within the working bandwidth. All of above make the MIMO antenna a potential candidate for mobile terminal-based MIMO antenna systems.

Recent Advances in Wearable Antenna Technologies: A Review

Abstract: Wearable antennas have received a great deal of popularity in recent years owing to their enticing characteristics and opportunities to realize lightweight, compact, low-cost, and versatile wireless communications and environments. These antennas must be conformal, and they must be built using lightweight materials and constructed in a low-profile configuration when mounted on various areas of the human body. These antennas ought to be able to function close to the human body with limited deterioration. These criteria render the layout of wearable antennas demanding, particularly when considering factors such as investigating the usability of textile substrates, high conductive materials during fabrication processes, and the effect of body binding scenarios on the performance of the design. Although there are minor differences in magnitude based on the implementations, several of these problems occur in the body-worn deployment sense. This study addresses the numerous problems and obstacles in the production of wearable antennas, their variety of materials, and the techniques of manufacturing alongside with bending scheme. This is accompanied by a summary of creative features and their respective approaches to address these problems recently raised by work in this area by the science community. © 2020. All Rights Reserved.

An Electrically Small Antenna Using Defected Ground Structure for RFID, GPS and IEEE 802.11 a/b/g/S Applications

Abstract: A compact size (20 × 21 mm2) planar tri-band electrically small antenna is presented for Wireless ISM, RFID application resonating at 1.57 GHz, 2.47 GHz and 926 MHz. The Proposed structure consists of a dual-slot radiating patch and two split ring structures made using combination of L and U shapes forming a defected ground structure (DGS). Length and width of the planar slot is optimized to get the required frequency bands whereas incorporation of DGS leads to increase in impedance bandwidth. The simulated and measured return losses (S11) of all three frequency bands are greater than 10 dB. Impedance bandwidths of 20 MHz (913–934 MHz), 90 MHz (1.5–1.59 GHz) and 70 MHz (2.43–2.50 GHz) are achieved for the proposed range. The electrically small antenna radiation pattern is omnidirectional, and gains of 0.32 dBi, 1.2 dBi and 1.5 dBi are achieved which make the antenna suitable for RFID, GPS and WLAN applications.