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E- and H-plane gain total radiation patterns of structurally deformable wearable antenna: (a) 5.2 GHz and (b) 5.8 GHz.
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A compact, low-profile wearable antenna capable of operation within the 5.1–5.46 GHz and 5.7–5.85 GHz medical body-area network band is suggested to make the antenna better for wearable devices. The integrated metasurface (MSs) antenna consists of as few as array of three wan-shaped components, directly below the planar waveguide-fed monopole anten...
Citations
... Year SAR (W/Kg) (1 g) SAR (W/K [46] 2020 (sim) 0.35 0.2 [47] 2020 (sim) 1.22 - [48] 2021 (sim) 0.29/0.2/0.22 0.13/0.0 [49] 2021 (sim) 0.9 - [50] 2022 (sim) 0.37 0.2 [51] 2020 (sim) 5.95 - [52] 2021 (sim) 0.25 0.5 [53] 2021 (sim) 36.3 44 [54] 2019 (sim) 0.3 - [55] 2019 (sim) 0.6 - [56] 2020 (sim) 0.84 - [57] 2019 (sim) -1. [58] 2021 (sim) 0.9 - ...
This study proposed the dimensions of 55 mm × 34 mm × 1 mm for wearable antenna; the copper Y-slot patch and copper partial ground are attached to a felt substrate. The partial ground has the higher impact in antenna gain enhancement compared with the full ground, making it the most suitable candidate for wearable applications and suitable for embedding in fabrics for use in medical applications. In addition, the proposed antenna design combined a fabric–metal barrier operated at 2.4 GHz 65.4% with a low specific absorption rate (SAR) of 0.01 watts per kilogramme (W/kg) and 0.006 W/kg per 10 g and a gain of 6.48 dBi. The proposed antenna has an omnidirectional radiation pattern. The two-layer barrier is designed to achieve high electromagnetic (EM) absorption and reduce the antenna’s absorption coefficient (SAR) for safe use in applications involving human activities. Simulation and measurement results on the arm and the head of the human body indicated that the antenna has excellent performance. In addition, the measurement results agreed well with the simulation results, making the proposed wearable antenna reliable for medical and 5G applications.
... However, UWB technology is more famous for WBAN applications than conventional narrowband wireless communication systems because of its advantages [7] such as high capacity, low-power transmission, and high reliability [8]. The antennas used in WBAN must be small, flexible, low in weight, and ideally comfortable for wearable devices [9]. ...
... Metamaterial structures are used as reflectors for single-band [37], dual-band [34,38], and wideband [39] applications to improve the performance and reduce the overall thickness of the conventional patch antenna. Metamaterials are expanded by arranging electrically small scatters into two dimensions, given the name metasurface owing to their low-profile, low loss, and ease of design [9]. This is due to the decreased backscattered radiation, preventing the propagation of antennas in a certain direction. ...
... Rogers duriod substrate is referred to as semi-flexible because of minimum thickness less than 1.6 mm. Due to its thinness and simplicity of manufacture, researchers suggest employing this material to construct lightweight antenna for biomedical application [9][15] [17] [23]. The material utilised in the bodyworn antenna should be flexible rather than rigid. ...
... For further improvement of antenna gain and directivity can be increased while back radiation is decreased and refracted by embedding metasurfaces at backend and ensure that -90 0 reflection phase occurs at targeted bands. The dispersion characteristics of surface waves or the attributes of reflection and refractive index are controlled by thin metasurfaces [23][24][25]. Less reflected back radiation can be achieved by using Electromagnetic Band Gap (EBG) technique that turns to yield low SAR value [28] [30]. When its reflection phase extends from -90° to +90°, the EBG behaves as an artificial magnetic conductor which can suppress the surface wave at specified operational frequencies [31][32][33][34]. ...
In recent years, wearable antenna demand in biomedical applications has increased drastically. Several effective techniques and efficient structures of antenna were proposed to overcome the challenges with respect to the vicinity of the human body. In this paper, substrate and conductive material for the wearable antenna are reviewed thoroughly to ensure that it operates consistently and with flexibility. The design of wearable antennas becomes challenging when flexible substrates are examined, better conductive materials are employed during manufacturing processes and the issue exists in body-worn implementation. To address these issues in this paper, exhaustive literature is carried out based on validated characteristics such as Specific Absorption Rate (SAR), gain, and bandwidth by employing radiating structure, feed, ground, and slot optimization. Effective topologies for gain enhancement, bandwidth enhancement, and SAR reduction for various wearable antenna designs on biomedical applications were reviewed through qualitative study. This extensive study on flexible and wearable technology explores the various problems and challenges involved while designing suitable antennas are discussed. This review paper also highlights the advancements in 5G technology, applications on ISM band and IOT, with particular emphasis on wearable antennas and their potential applications in the biomedical field.
... Metasurfacebased antenna improves the radiation characteristics and energy absorption from the human tissue. Furthermore, low SAR and high front-to-back ratio are suitable for body area wearable applications [15]. ...
Wireless body area network (WBAN) incorporates a wireless sensor network and wearable devices in miniature size. In this paper, a dual-band microstrip patch (DBMSP) antenna as a sensor with a modified split ring resonator (SRR) and defective ground structure (DGS) is proposed for muscle mass measurement and prediction. Modified SRR on the ground plane forms a defected ground structure (DGS) for back radiation reduction and suits muscle mass measurement. The proposed dual-band microstrip patch antenna resonates at 5.2 GHz and 8.4 GHz, with impedance bandwidth of about 0.9 GHz and 1.89 GHz, input reflection coefficient is about -21.12 dB and -14.5 dB, respectively. This DBMSP antenna has an efficiency of 99.9%, with a negligible amount of specific absorption rate (SAR). From the proposed DBMSP antenna sensor, muscle mass is predicted from human muscle. The proposed antenna is fixed on the ventral surface of the forearm and biceps. DBMSP antenna sensor detects electromagnetic energy from muscle tissues under radiating near-field conditions. The muscle tissue signal is acquired through the proposed DBMSP antenna. The acquired antenna process with nondecimated wavelet transform (NDWT) and discrete wavelet transform (DWT) algorithms for noise reduction. Further, early prediction of muscle mass prevents humans from lack of protein and oxygen levels in the blood and avoids major issues in human health. The proposed DBMSP antenna-based muscle mass measurement achieves 89% accuracy when compared with laboratory measurement.
... Employing slits and slots on the antenna structure was presented in [6]. Loading a metamaterial structure as part of the microstrip antenna is also reported [7,9]. ...
This paper presents the design of a novel fabric-based multi-band microstrip antenna in mm-wave frequencies for wearable applications. The reference patch antenna was etched on a flexible polytetrafluoroethylene (PTFE) fabric substrate with an overall dimension of 18 mm × 18 mm × 0.6 mm and optimized the patch geometry using a binary-coded genetic algorithm. The algorithm iteratively creates a new shape of the path surface, evaluates the cost function, and returns the best-fitted geometry based on the formulated fitness function. The free space and on-body simulation of the best-fitted antenna performance parameter was investigated and analyzed. In free space, the proposed antenna is resonant at five distinct frequencies: 27.8 GHz, 30.3 GHz, 40.1 GHz, 47.2 GHz, and 56.7 GHz. The antenna achieves a wide bandwidth of 0.69, 2.32, 2.22, 1.76, and 8.11 GHz and an improved broadside directivity of 10.3, 8.5, 7.8, 9.6, and 8.9 dB in free space, respectively. For on-body analysis, the antenna was simulated using a three-layer human body phantom model at three distinct distances. The gain and radiation efficiency were significantly reduced when the antenna was close to the phantom model and gradually enhanced as the gap increased. Moreover, the antenna performances were evaluated and compared by using four additional fabric substrates. Because of its excellent on-body performance with flexible textile-based substrates, the optimized antenna is a suitable candidate for multi-band body-centric communications.
... Thus, to meet the challenges arising due to the extensive use of flexible devices, a flexible antenna with high performance parameters is required. So far, only a limited number of publications can be found on the design of multiband flexible antenna for targeted band spectra [4][5][6][7][8][9][10][11]. For instance, in [4] a serpentine-based dual band antenna for flexible applications is presented. ...
... The antenna offers wide bandwidth, but has disadvantages like bigger size and no information the gain of the presented design. A metasurface loaded high gain antenna was presented in [7]. Although high gain and broad bandwidth was achieved, the use of metasurfaces increases the structural complexity with high profile and increased physical dimensions. ...
... The design structure of EBG cell in Figure 5(d) simulated and implemented in (19) to get the dual band of operation. There are some dual bands EBG performance is being reported in literature, but when the based and conductive material is textile than the design of EBG cell must play a key role. ...
... In Figure 7(a), shows the surface current when adaptive pass resonance frequency is being set at 2.45 GHz with 0 0 phase angle, (b) represents when the phase is shifted to 30 0 . Figure 7 (19) (e) The dual band EBG cell integrated with Patch antenna in literature (19) In Figure 8, the dispersion of unit EBG cell is represented. The EBG does not permits to flow the surface waves for specific frequency. ...
... In Figure 7(a), shows the surface current when adaptive pass resonance frequency is being set at 2.45 GHz with 0 0 phase angle, (b) represents when the phase is shifted to 30 0 . Figure 7 (19) (e) The dual band EBG cell integrated with Patch antenna in literature (19) In Figure 8, the dispersion of unit EBG cell is represented. The EBG does not permits to flow the surface waves for specific frequency. ...
Background/Objectives: Flexible electronics have paved the way for Wireless Body Area Networks (WBAN). The main challenge in accommodating such applications is reducing the impact of radiation on the human body. The presence of body tissues may affect WBAN devices such as wearable sensors and wearable antennas, so reducing back radiations becomes an important task. Methodology: When a microstrip patch antenna is placed on a human body, the artificially formed Electromagnetic Band Gap (EBG) surface mimics the property of a Perfect Magnetic Conductor (PMC) rather than the
conventional Perfect Electrical Conductor (PEC). Findings: In this work, the unique property of the EBG surface beneath the patch antenna creates a zero phase shift at the resonance, which improves the antenna’s performance and reduces back radiations as well. The proposed EBG surface structure is the simplest square-shaped structure with no conductor connections Via patch (Via-less). Novelty: The EBG structure designed and presented in this paper has zero reflections for the dual-band of operations. The resonance frequency
of 2.45GHz and 5.5 GHz has been designed for the absorption of 80% and 65% respectively. This level of absorption has not yet been reported in the literature. The newly formed EBG cell integrated with the patch antenna and its performance improvements has been shown. The analysis shows that the EBG enhances the return loss by 20.35 % and gain enhances by 16.44 %, on textile materials with the advantage of most simplex EBG cell construction.
Keywords: EBG; PMC; PEC; Wearable Microstrip Patch Antenna; WBAN
... Electric field and SAR have a one-to-one relationship. It is possible to determine the SAR (W/kg) given the electric field, E (V/m), conductivity of the material, σ (S/m), and the density of the material, ρ (kg/m 3 ) [22]. ...
... It is also worth noting that even though the overall size of the antenna proposed by the authors in Ref. 8 is small compared to our Bio-EBG-iwA, yet the efficiency of their proposed antenna was not reported which raises a question as to the workability of the antenna when in closed proximity to HTM. The same issue applies to the work reported in Ref. 25. It can also be observed from Table 4 that the antenna proposed in Refs. ...
A compact bio-inspired electromagnetic bandgap integrated wearable antenna (Bio-EBG-iwA) is proposed in this work. The Bio-EBG-iwA is based on the hybridization of semi-Vitis vinifera leaf-shaped patch, asymmetric feedline, reflected G-shaped slot, partial ground, and a stub on the ground plane. The antenna is built on the locally made textile material called Aso-oke (Alari) with permittivity and a loss tangent of 1.43 and 0.019, respectively. The dimension of the proposed antenna is 0.2λg X 0.1λg X 0.0089λg (22mm X 12mm X 0.7mm) at 2.45 GHz. Despite its compactness, the gain of -0.48 and 2.5 dBi are achieved at 2.45 and 5.7 GHz respectively without electromagnetic bandgap (EBG). A dual-band textile-based uniplanar compact electromagnetic bandgap (UC-EBG) is introduced to create isolation between the human tissue and the antenna. The dual-band UC-EBG is realized through the use of a modified slitted-square ring (MSSR) and the 90-degree rotated H-shaped patch on Aso-oke (Alari) with a thickness of 2.1 mm. The periodicity of the proposed UC-EBG is
34.5 mm. The antenna is placed on a 2 X 2 array of the proposed UC-EBG separated by a 3 mm foam thickness. The radiation efficiency of 88.97% and 79.85% are achieved at 2.45 and 5.7 GHz respectively. The gain of the proposed UC-EBG integrated antenna increased from -0.48 and 2.5 dBi to 5.9 and 10.7 dBi at 2.45 and 5.7 GHz, respectively. The front-to-back ratio (FBR) of 26.3 dB is achieved with the use of UC-EBG. The use of UC-EBG results in a 98.31% and 99.4% reduction in average SAR at 2.45 and 5.7 GHz, respectively.
The off-body and on-body performance analysis of the proposed UC-EBG integrated antenna show that the proposed EBG integrated antenna (Bio-EBG-iwA) is a suitable candidate for wearable application. To the best of our knowledge, this is the most compact wearable antenna with suitable gain, radiation efficiency, and high FBR. In addition, our proposed UC-EBG shows that slitting is an effective way of miniaturizing the EBG structure.
... During the implementation of the process, the meta-surface antenna is designed using three components that are wan-shaped structure and placed under the waveguide-fed monopole antenna. This design approach resulted in a wearable antenna that has achieved a low specific absorption rate of 0.84 W/kg when compared to other wearable device antenna [24]. Lin et al. (2020) designed an ultra-wide band textile antenna to support microwave medical imaging applications. ...
In medical applications, most of the patients are remotely monitored to eliminate the risk of being infected from the healthcare facilities. The process of remotely monitoring patients involves placing several body sensor networks on the patient’s body to collect their health details. The collected information is transmitted via the wireless communication process that must be of a high quality. Hence, this paper investigated antenna S11 variation (AS11V) with harmonic suppression to improve the communication process in medical applications. In this research, the antenna was placed on a 2- to 4-mm thickness belt, 15 to 300 mm body thickness, and 40 to 50 dielectric constants. In addition, 3-short pin resonators were used in the harmonic suppression process aid in reducing the unnecessary harmonics in the communication process. Optimized recurrent neural networks (ORNN) were then used to process the wearable antenna–based collected devices. This in return helped in determining how effectively the gathered data helps in the medical analysis. The efficiency of the wireless antenna–based communication process was then evaluated using simulation results, and the ORNN approach showed 99.17% accuracy using the collected and validated data.
