scholarly journals Small Antennas for Wearable Sensor Networks: Impact of the Electromagnetic Properties of the Textiles on Antenna Performance

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5157
Author(s):  
Gabriela Atanasova ◽  
Nikolay Atanasov
Keyword(s):  
Sensor Networks ◽  
Loss Tangent ◽  
Rapid Development ◽  
Substrate Material ◽  
Radiation Efficiency ◽  
Electromagnetic Properties ◽  
Textile Materials ◽  
Antenna Performance ◽  
Low Profile ◽  
The Impact

The rapid development of wearable wireless sensor networks (W-WSNs) has created high demand for small and flexible antennas. In this paper, we present small, flexible, low-profile, light-weight all-textile antennas for application in W-WSNs and investigate the impact of the textile materials on the antenna performance. A step-by-step procedure for design, fabrication and measurement of small wearable backed antennas for application in W-WSNs is also suggested. Based on the procedure, an antenna on a denim substrate is designed as a benchmark. It demonstrates very small dimensions and a low-profile, all while achieving a bandwidth (|S11| < −6 dB) of 285 MHz from 2.266 to 2.551 GHz, radiation efficiency more than 12% in free space and more than 6% on the phantom. Also, the peak 10 g average SAR is 0.15 W/kg. The performance of the prototype of the proposed antenna was also evaluated using an active test. To investigate the impact of the textile materials on the antenna performance, the antenna geometry was studied on cotton, polyamide-elastane and polyester substrates. It has been observed that the lower the loss tangent of the substrate material, the narrower the bandwidth. Moreover, the higher the loss tangent of the substrate, the lower the radiation efficiency and SAR.

scholarly journals Bandwidth-Enhanced Low-Profile Antenna with Parasitic Patches

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Son Xuat Ta ◽  
Kam Eucharist Kedze ◽  
Dao Ngoc Chien ◽  
Ikmo Park
Keyword(s):  
Ground Plane ◽  
Axial Ratio ◽  
Radiation Efficiency ◽  
Electric Conductor ◽  
Physical Size ◽  
Bandwidth Enhancement ◽  
Antenna Performance ◽  
Low Profile ◽  
Linearly Polarized ◽  
The Cost

This paper presents low-profile broadband antennas, which are composed of four parasitic patches placed between planar radiators and a perfect electric conductor ground plane. Two types of planar radiators, a conventional dipole and a crossed dipole, are employed to produce linearly polarized (LP) and circularly polarized (CP) radiations, respectively. The radiator and parasitic patches are realized on thin substrates to lower the cost. Owing to the presence of parasitic patches, the antenna performance improves in terms of profile reduction, resonant frequency decrease, and bandwidth enhancement. These improvements are discussed and confirmed computationally and experimentally. The LP design with the overall dimensions of 120 mm × 120 mm × 16.3 mm (0.64λ0 × 0.64λ0 × 0.087λ0 at 1.6 GHz) has a |S11| < −10 dB bandwidth of 1.465–1.740 GHz (17.2%), a broadside gain of 8.5–8.8 dBi, and a radiation efficiency > 96%. The CP design, which has the same physical size as the LP case, has a |S11| < −10 dB bandwidth of 1.388–1.754 GHz (23.3%), a 3 dB AR (axial ratio) bandwidth of 1.450–1.685 GHz (15.0%), a right-hand CP broadside gain of 7.8–8.7 dBic, and a radiation efficiency > 90%.

scholarly journals A Low Profile Ultrawide Band Monopole Antenna for Wearable Applications

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Srinivas Doddipalli ◽  
Ashwin Kothari ◽  
Paritosh Peshwe
Keyword(s):  
Free Space ◽  
Specific Absorption Rate ◽  
Monopole Antenna ◽  
Human Tissues ◽  
Radiation Characteristics ◽  
Wide Bandwidth ◽  
Overall Design ◽  
Antenna Performance ◽  
Low Profile ◽  
The Impact

A low profile pentagonal shaped monopole antenna is designed and presented for wearable applications. The main objective of this paper is to design a miniaturized ultrawide band monopole planar antenna which can work efficiently in free space but also on the surface of the human body. The impact of human tissues on antenna performance is explained using the proposed pentagonal monopole antenna. The antenna is designed with a pentagonal radiator and a matched feed line of 50 ohm and square slots are integrated on defected ground of FR4 substrate with a size of 15 mm × 25 mm to achieve ultrawide band (UWB) performance in free space and human proximity. This overall design will enhance the antenna performance with wide bandwidth ranging from 2.9 GHz to 11 GHz. Specific absorption rate (SAR) of the proposed antenna on dispersive phantom model is also measured to observe the exposure of electromagnetic energy on human tissues. The simulated and measured results of the proposed antenna exhibit wide bandwidth and radiation characteristics in both free space and human proximity.

scholarly journals Many-Objective Automated Optimization of a Four-Band Antenna for Multiband Wireless Sensor Networks

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3309 ◽  
Author(s):  
Łukasz Januszkiewicz ◽  
Paolo Di Barba ◽  
Łukasz Jopek ◽  
Sławomir Hausman
Keyword(s):  
Wireless Sensor Networks ◽  
Sensor Networks ◽  
Impedance Matching ◽  
Radiation Efficiency ◽  
Ultra Wideband ◽  
Wireless Sensor ◽  
Initial Design ◽  
Antenna Performance ◽  
Final Design ◽  
Automated Optimization

This paper describes a new design and an optimization framework for a four-band antenna to be used in wireless sensor networks. The antenna is designed to operate effectively in two open frequency bands (ISM—Industrial, Scientific, Medical), 2.4 GHz and 5.8 GHz, as well as in two bands allocated for the fifth-generation (5G) cellular networks, 0.7 GHz and 3.5 GHz. Our initial design was developed using the trial and error approach, modifying a circular disc monopole antenna widely used in ultra wideband (UWB) systems. This initial design covered the three upper bands, but impedance matching within the 700 MHz band was unsatisfactory. The antenna performance was then improved significantly using an optimization algorithm that applies a bi-objective fully-Paretian approach to its nine-parameter geometry. The optimization criteria were impedance matching and radiation efficiency. The final design exhibits good impedance matching in all four desired bands with the Voltage Standing Wave Ratio (VSWR) value below 2 and radiation efficiency of 88%. The simulated antenna performance was verified experimentally.

scholarly journals Performance Characteristics of Head-Worn Antenna based on Dielectric Substrate Over WBAN Application

2018 ◽  
Vol 7 (4.30) ◽  
pp. 403
Author(s):  
Abdul Rashid .O. Mumin ◽  
R. Alias ◽  
Jiwa Abdullah ◽  
Raed A Abdulhasan ◽  
Samsul Haimi Dahlan ◽  
...  
Keyword(s):  
Radiation Pattern ◽  
Free Space ◽  
Human Head ◽  
Dielectric Substrate ◽  
Performance Characteristics ◽  
Electromagnetic Properties ◽  
Head Model ◽  
Antenna Performance ◽  
Loss Efficiency ◽  
The Impact

Performance characteristics of head-worn antenna based on dielectric substrate for WBAN application with various dielectric constant for square slot patch antenna are demonstrated in this paper. The impact of Electromagnetic (EM) energy from antenna towards human head and on antenna performance changes due to human head proximity are explored in this paper. The human head exposed to 5.8 GHz on ISM frequency band and radiation pattern, return loss, efficiency, and bandwidth and SAR distribution value performance have been thoroughly explored. However, decreasing the antenna size is a great topic ‎of antenna development, which differentiates antenna performance for a small antenna. Multilayered human head phantom having five layers are constructed based on different tissues and these tissues represent human head parts such as (Skin, fat, Cerebrospinal fluid (CSF), bone and brain), all of each tissues are based on their electromagnetic properties and set at 5.8GHz.The proposed antenna with human head model simulated through (FDTD) using CST and variation of parameters of antenna with MATLAB.  Antenna with FR4 substrate produces the highest SAR values while antenna with RT5880 substrate has the lowest SAR value 0.206 W/kg and 0.0784 W/kg at 5.8 GHz frequency exposed for 10g tissue respectively. It can be observed that the radiation pattern shows that the antenna gain with substrate of Rogers RT5880 is increased from front –to-back from 7.1 to 7.29 dB in the free space and on human head respectively. A good agreement between simulation and measurements in free space are obtained. The presented prototype has a potential to work for ISM applications.

Research on behavior recognition based on feature fusion of automatic coder and recurrent neural network

2020 ◽  
Vol 39 (6) ◽  
pp. 8927-8935
Author(s):  
Bing Zheng ◽  
Dawei Yun ◽  
Yan Liang
Keyword(s):  
Neural Network ◽  
Recurrent Neural Network ◽  
Behavior Pattern ◽  
Rapid Development ◽  
Video Data ◽  
Support Vector ◽  
Behavior Recognition ◽  
Learning Methods ◽  
The Impact ◽  
Internet Of Things Technology

Under the impact of COVID-19, research on behavior recognition are highly needed. In this paper, we combine the algorithm of self-adaptive coder and recurrent neural network to realize the research of behavior pattern recognition. At present, most of the research of human behavior recognition is focused on the video data, which is based on the video number. At the same time, due to the complexity of video image data, it is easy to violate personal privacy. With the rapid development of Internet of things technology, it has attracted the attention of a large number of experts and scholars. Researchers have tried to use many machine learning methods, such as random forest, support vector machine and other shallow learning methods, which perform well in the laboratory environment, but there is still a long way to go from practical application. In this paper, a recursive neural network algorithm based on long and short term memory (LSTM) is proposed to realize the recognition of behavior patterns, so as to improve the accuracy of human activity behavior recognition.

Challenges and Issues in the Design of Micro-Machined Antennas - A Review

2020 ◽  
Vol 13 ◽  
Author(s):  
Ashish Kumar ◽  
Amar Partap Singh Pharwaha
Keyword(s):  
Patch Antenna ◽  
Ground Plane ◽  
Substrate Material ◽  
Review Article ◽  
High Index ◽  
Performance Characteristics ◽  
Machining Process ◽  
Patch Antennas ◽  
Micro Machining ◽  
The Impact

Background: Patch antennas are composed of the substrate material with patch and ground plane on the both sides of the substrate. The dimensions and performance characteristics of the antenna are highly influenced by the choice of the appropriate substrate depending upon the value of their dielectric constant. Generally, low index substrate materials are used to design the patch antenna but there are also some of the applications, which require the implementation of patch antenna design on high index substrate like silicon and gallium arsenide. Objective: The objective of this article is to review the design of antennas developed on high index substrate and the problems associated with the use of these materials as substrate. Also, main challenges and solutions have been discussed to improve the performance characteristics while using the high index substrates. Method: The review article has divided into various sections including the solution of the problems associated with the high index substrates in the form of micro-machining process. Along with this, types of micro machining and their applications have discussed in detail. Results: This review article investigates the various patch antennas designed with micro-machining technology and also discusses the impact of micro-machining process on the performance parameters of the patch antennas designed on high index substrates. Conclusion: By using the micro-machining process, the performance of patch antenna improves drastically but fabrication and tolerances at such minute structures is very tedious task for the antenna designers.

On the devaluation of expert opinion or why do we need a law about the basics of expert activity

2020 ◽  
Vol 22 (3) ◽  
pp. 19-24
Author(s):  
MARAT R. BIKTIMIROV ◽  
◽  
OLGA V. PILIPENKO ◽  
MAXIM S. SAFONOV ◽  
◽  
...  
Keyword(s):  
Project Management ◽  
Structural Analysis ◽  
Expert Opinion ◽  
Knowledge Economy ◽  
Rapid Development ◽  
Digital Technologies ◽  
Accurate Assessment ◽  
Industrial Management ◽  
The Impact ◽  
Creative Construction

Taking practical responsible decisions in the field of social and industrial management in the context of rapid development of digital technologies in the era of the knowledge economy is impossible without reliance on expertise. A kind of organization of activities for the production of ‘predictions’ is required, when not only an accurate assessment of the impact of certain factors and their possible interactions with each other is given, but also as a result of creative construction of scenarios for the development of processes and events, an understanding comes which factors need to be taken into account. At the same time, the expertise constantly faces criticism, calling the conclusions of experts arbitrary, unreliable and subjective. Often, expertise is confused with monitoring, evaluation, diagnosis, inspection or counseling. The authors of the article carried out a structural analysis of the content of the expertise processes in the project management vector in the digitalization era and came to the conclusion that the effectiveness of the expertise is significantly increased in case of clear regulation of this type of activity, providing the necessary status.

scholarly journals Preparation and electromagnetic properties characterization of reduced graphene oxide/strontium hexaferrite nanocomposites

2020 ◽  
Vol 9 (1) ◽  
pp. 105-114 ◽  
Author(s):  
Shumin Du ◽  
Huaiyin Chen ◽  
Ruoyu Hong
Keyword(s):  
Electromagnetic Wave ◽  
Environmental Pollution ◽  
Electromagnetic Interference ◽  
Electromagnetic Waves ◽  
Rapid Development ◽  
Living Environment ◽  
World Health ◽  
Electromagnetic Properties ◽  
Strontium Hexaferrite ◽  
Wave Radiation

AbstractWith the rapid development of electronics and information technology, electronics and electrical equipment have been widely used in our daily lives. The living environment is full of electromagnetic waves of various frequencies and energy. Electromagnetic wave radiation has evolved into a new type of environmental pollution that has been listed by the WHO (World Health Organization) as the fourth largest source of environmental pollution after water, atmosphere, and noise. Studies have shown that when electromagnetic wave radiation is too much, it can cause neurological disorders. And electromagnetic interference will cause the abnormal operation of medical equipment, precision instruments and other equipment, and therefore cause incalculable consequences. Therefore, electromagnetic protection has become a hot issue of concern to the social and scientific circles.

scholarly journals A Whole Virion Vaccine for COVID-19 Produced via a Novel Inactivation Method and Preliminary Demonstration of Efficacy in an Animal Challenge Model

Vaccines ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 340
Author(s):  
Izabela K Ragan ◽  
Lindsay M Hartson ◽  
Taru S Dutt ◽  
Andres Obregon-Henao ◽  
Rachel M Maison ◽  
...  
Keyword(s):  
Vaccine Candidate ◽  
Rapid Development ◽  
Neutralizing Antibody ◽  
Emerging Diseases ◽  
Effective Vaccine ◽  
Preliminary Evaluation ◽  
Sequencing Data ◽  
Post Challenge ◽  
Vaccine Candidates ◽  
The Impact

The COVID-19 pandemic has generated intense interest in the rapid development and evaluation of vaccine candidates for this disease and other emerging diseases. Several novel methods for preparing vaccine candidates are currently undergoing clinical evaluation in response to the urgent need to prevent the spread of COVID-19. In many cases, these methods rely on new approaches for vaccine production and immune stimulation. We report on the use of a novel method (SolaVAX) for production of an inactivated vaccine candidate and the testing of that candidate in a hamster animal model for its ability to prevent infection upon challenge with SARS-CoV-2 virus. The studies employed in this work included an evaluation of the levels of neutralizing antibody produced post-vaccination, levels of specific antibody sub-types to RBD and spike protein that were generated, evaluation of viral shedding post-challenge, flow cytometric and single cell sequencing data on cellular fractions and histopathological evaluation of tissues post-challenge. The results from this preliminary evaluation provide insight into the immunological responses occurring as a result of vaccination with the proposed vaccine candidate and the impact that adjuvant formulations, specifically developed to promote Th1 type immune responses, have on vaccine efficacy and protection against infection following challenge with live SARS-CoV-2. This data may have utility in the development of effective vaccine candidates broadly. Furthermore, the results of this preliminary evaluation suggest that preparation of a whole virion vaccine for COVID-19 using this specific photochemical method may have potential utility in the preparation of one such vaccine candidate.

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