scholarly journals Input Impedance Analysis of Wearable Antenna and Experimental Study with Real Human Subjects: Differences between Individual Users

Electronics ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1152
Author(s):  
Dairoku Muramatsu ◽  
Ken Sasaki
Keyword(s):  
Human Body ◽  
Input Impedance ◽  
Human Subjects ◽  
Impedance Analysis ◽  
The Body ◽  
Design Parameters ◽  
Moisture Condition ◽  
Wearable Antenna ◽  
Body Tissues ◽  
Impedance Characteristics

In human body communication (HBC) systems, radio-frequency signals are excited in the human body through a wearable antenna comprised of electrodes that are in contact with the surface of the body. The input impedance characteristics of these antennas are important design parameters for increasing transmission efficiency and reducing signal reflection, similar to other wireless circuits. In this study, we discuss variations of input impedance characteristics of a wearable antenna prototype caused by differences among real human subjects. A realistic human arm model is used for simulations, and the analytical results obtained are compared to measured data obtained from real human subjects, in a range from 1 to 100 MHz. The simulations of input impedance characteristics from antennas worn on the wrists of male and female models with dry and wet skin conditions show that the impedance variation between genders is small. The moisture condition of the skin has little influence on frequencies exceeding several MHz. Measurements with a proto-type wearable antenna and 22 real human subjects reveal that HBC is robust against the variations of individual users from the viewpoint of the voltage standing wave ratio. Moreover, a simplified rectangular prism model is proposed to analyze the thickness of body tissues. Comparisons of measured input impedances indicate that individual differences in impedance are mainly due to differences in the thickness of skin and fat layers. The model also enables us to design the antenna prototype without multiple subject experiments.

Dynamic ease evaluation for 3D garment design

2018 ◽  
Vol 22 (2) ◽  
pp. 209-222
Author(s):  
Fangfang Zhang ◽  
Trevor John Little
Keyword(s):  
Human Body ◽  
Design Methodology ◽  
Human Subjects ◽  
Essential Element ◽  
The Body ◽  
Upper Arm ◽  
Core Element ◽  
Content Type ◽  
Comfort Evaluation ◽  
Garment Design

Purpose 3D garment design technology is developing rapidly thereby creating a need for different approaches to developing the patterns. The purpose of this paper is to evaluate the 3D dynamic ease distribution for a 3D garment design. Design/methodology/approach Standard garments were created from Size 2 to Size 14 for ten human subjects. Landmarks location on both human body and the standard garment under dynamic postures are recorded, and he fit and comfort evaluation of the standard garment were collected from the ten human subjects. Finally, these data were used to evaluate the 3D dynamic ease distribution for a 3D garment design. Findings 3D dynamic ease evaluation is challenging and the findings showed that the upper-arm design is a core element of the whole 3D garment design. The upper arm is not only a connecting part for both front and back pieces of the garment, but is also the main active part of the body, so it is the essential element to affect the comfort and fit of the garment under dynamic postures. Originality/value This research provides a novel 3D ease evaluation by analyzing the landmarks location of both human body and standard garment, and fit and comfort evaluation of the standard garment, which are all carried under dynamic postures.

scholarly journals Impedance Matching of Axial Mode Helical Antennas

2021 ◽  
Vol 20 ◽  
pp. 66-69
Author(s):  
Hossein Mardani ◽  
Neil Buchanan ◽  
Robert Cahill ◽  
Vincent Fusco
Keyword(s):  
Input Impedance ◽  
Impedance Matching ◽  
Ground Plane ◽  
Center Frequency ◽  
Design Parameters ◽  
Axial Mode ◽  
Impedance Characteristics ◽  
Measurement Results ◽  
Line Theory ◽  
Helical Antennas

In this paper, we study the input impedance characteristics of axial mode helical antennas to find an effective way for matching it to 50 Ω. The study is done on the important matching parameters such as like wire diameter and helix to the ground plane gap. It is intended that these parameters control the matching without detrimentally affecting the radiation pattern. Using transmission line theory, a simple broadband technique is proposed, which is applicable for perfect matching of antennas with similar design parameters. We provide design curves to help to choose the proper dimensions of the matching section based on the antenna’s unmatched input impedance. Finally, using the proposed technique, a 4-turn axial mode helix is designed at 2.5 GHz center frequency and the measurement results of the manufactured antenna will be included. This parametric study gives a good insight into the input impedance characteristics of axial mode helical antennas and the proposed impedance matching approach provides a simple, useful method for matching these types of antennas.

Design and Analysis of Wearable Antennas

2021 ◽  
pp. 85-97
Author(s):  
Mahesh Kumar Aghwariya ◽  
Amit Kumar ◽  
Ragini Sharma
Keyword(s):  
Wireless Communication ◽  
Human Body ◽  
The Body ◽  
Antenna Design ◽  
Maximum Efficiency ◽  
Wearable Antenna ◽  
Wearable Antennas ◽  
Flexible Material

This chapter presents the various designing methods and challenges associated with wearable antennas, selecting the designing material, various fabrication techniques, and implementation methods on the fabric. Wearable antennas have gained popularity in recent years due to their unmatched properties and unique features. The wearable antenna is capable of providing effective wireless communication, tracking, and sensing. These types of antenna need to be conformal when used on numerous parts of the human body, and they need to be lightweight, flexible, and must be implemented easily on the flexible material. These antennas must be capable of operating with maximum efficiency on the human body. These requirements make the wearable antenna design challenging. They also need to be compact in size, better in coupling with the body, and must be capable of handling issues associated with the device when the target is moving.

scholarly journals An Online Method to Detect and Locate an External Load on the Human Body with Applications in Ergonomics Assessment

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4471
Author(s):  
Marta Lorenzini ◽  
Wansoo Kim ◽  
Elena De Momi ◽  
Arash Ajoudani
Keyword(s):  
Human Body ◽  
External Load ◽  
Sagittal Plane ◽  
Human Subjects ◽  
Vertical Component ◽  
Industrial Applications ◽  
The Body ◽  
Whole Body ◽  
Contact Points ◽  
Reaction Forces

In this work, we propose an online method to detect and approximately locate an external load induced on the body of a person interacting with the environment. The method is based on a torque equilibrium condition on the human sagittal plane, which takes into account a reduced-complexity model of the whole-body centre of pressure (CoP) along with the measured one, and the vertical component of the ground reaction forces (vGRFs). The latter is combined with a statistical analysis approach to improve the localisation accuracy, (which is subject to uncertainties) to the extent of the industrial applications we target. The proposed technique eliminates the assumption of known contact position of an external load on the human limbs, allowing a more flexible online body-state tracking. The accuracy of the proposed method is first evaluated via a simulation study in which various contact points on different body postures are considered. Next, experiments on human subjects with three different contact locations applied to the human body are presented, revealing the validity of the proposed methodology. Lastly, its benefit in the estimation of human dynamic states is demonstrated. These results add another layer to the online human ergonomics assessment framework developed in our laboratory, extending it to more realistic and varying interaction conditions.

scholarly journals THERMAL AWARE LINK ENERGY EFFICIENT SCHEME FOR BODY AREA NETWORKS

2020 ◽  
Vol 15 (12) ◽  
Author(s):  
M. Javed
Keyword(s):  
Human Body ◽  
Energy Efficient ◽  
Data Transfer ◽  
Body Area Networks ◽  
Residual Energy ◽  
The Body ◽  
Body Area ◽  
Body Tissues ◽  
Daunting Task ◽  
Efficient Scheme

A daunting task in Wireless Body Area Networks (WBANs) is still to develop Effective routing techniques. Small-sized nodes are installed on or within the human body to monitor human health conditions which then deliver the data to servers for analysis. During sensing and data transfer, biomedical sensors work continuously and the temperature of the nodes may rise beyond the threshold limit. This temperature rise may damage the human body tissues as well as the routing mechanism in terms of path losses. To keep the temperature at its normal working value, a priority-based selection of routes is required to prevent data loss during transmission. This will ensure safe and accurate data delivery at the destination. A protocol called “Thermal Aware Link Energy Efficient Scheme for WBANs” (TALEEBA) for workers is proposed to monitor the health of workers in factories. One of the four sinks will collect the data of the nearest worker in the field. As the body temperature of any worker is detected to rise, an alarm will be generated and the supervisor of the workplace will ask the worker to be replaced by some other worker. The same mechanism will continue till the task ends. Our proposed TALEEBA (Thermal Aware Link Energy Efficient Scheme for WBANs) scheme is aligned with current LAEEBA and THE-FAME WBAN schemes. In simulations, we analyze our protocol in terms of stability period, network lifetime, residual energy, a packet sent, packet dropped, and throughput. Hence, the results show stability and network life 50%, a packet sent 20% and throughput 23% are improved in comparison with LABEEA and THE-FAME protocols.

scholarly journals The Attenuation Characteristics of the Body Tissue on Frequency Function in WBAN Channel

2021 ◽  
Vol 5 (2) ◽  
Author(s):  
Achmad Mauludiyanto ◽  
Gamantyo Hendrantoro ◽  
Muhammad Fachry Nova
Keyword(s):  
Human Body ◽  
Wireless Body Area Network ◽  
The Body ◽  
Body Tissue ◽  
Frequency Function ◽  
Body Area Network ◽  
Area Network ◽  
Body Area ◽  
Body Tissues ◽  
Significant Difference

The Wireless Body Area Network (WBAN) refers to a communication network between sensors placed on the inside, on the surface, or around the body wirelessly. WBAN system cannot be separated from body tissues. Body tissues also have electrical properties depending on frequency. Therefore, body tissue can affect the phenomena occurring in radio wave propagation in the WBAN channel. One of the phenomena is attenuation. This study investigates the impacts of body tissue on the WBAN channel and the effects of frequency on the attenuation of body tissue in the WBAN channel. The measurement of magnitude response was carried out with the human body as the measurement object by utilizing the S21 parameter measurement with a vector network analyzer. In NLOS conditions, a human body was located between two coplanar Vivaldi antenna. Measurements were conducted on the head, chest, and abdomen. The frequency used was in the range of 2 GHz to 6 GHz. The body tissue attenuation was obtained by finding the difference between the magnitude measurement response on the LOS and NLOS conditions. The attenuation data were analyzed using statistical and numerical analysis to determine the effect of frequency on the attenuation of the human body tissues. Based on the analysis results, it was identified that the frequency affected the human body tissue attenuation. The enhancement attenuation of the human body tissues occurred when the frequency was higher. Moreover, there was a significant difference in the body tissue attenuation in different parts of the body.Keywords: attenuation, body tissues, s-parameters, wireless body area network.

scholarly journals Análisis de impedancia bioeléctrica (AIB) en la producción animal. Revisión

2021 ◽  
Vol 12 (2) ◽  
pp. 553-572
Author(s):  
Larissa Luísa Schumacher ◽  
Julio Viégas ◽  
Gilmar Dos Santos Cardoso ◽  
Anderson Bertoluzzi Moro ◽  
Tiago João Tonin ◽  
...  
Keyword(s):  
Body Composition ◽  
Ionic Current ◽  
Bioelectrical Impedance ◽  
Cost Effective ◽  
Impedance Analysis ◽  
The Body ◽  
Tissue Composition ◽  
Body Tissues ◽  
Different Levels ◽  
Potential Use

Bioelectrical impedance analysis (BIA) is a method based on the different levels of opposition to the flow of an ionic current through the different body tissues. Results are expressed by primary measures of resistance (Rs) and reactance (Xs). From such measures, equations are applied to determine the phase angle (PA) and impedance (Z). Bioimpedance analysis has been indicated as a reliable and precise method to determine the body composition and nutritional status in humans. BIA has recently been adapted to be applied on animal production. Therefore, the aim of this review is to provide an analysis on the potential use of bioelectrical impedance on zootechnical production. Through BIA, correlations among bioelectrical measures and tissue composition of swine, bovine, ovine, bubaline and fish carcasses can be established. In this regard, a growing number of demands were led by more precise and cost-effective methods to evaluate the body composition in the zootechnical sector, in which the analysis of bioelectrical impedance proved to be a promising and minimally invasive technology to replace traditional methods. 

scholarly journals Electrochemical behavior of various implantation biomaterials in the presence of various simulated body fluids: An overview

2021 ◽  
Vol 62 (3) ◽  
pp. 213-219
Author(s):  
John Santiagu ◽  
Devadoss Delinta ◽  
Asirvatham Ajila ◽  
Annamalai Selvam ◽  
Senthamarai Muthukumaran ◽  
...  
Keyword(s):  
Human Body ◽  
Corrosion Behaviour ◽  
Ringer Solution ◽  
Modern Medicine ◽  
Body Fluids ◽  
The Body ◽  
Carat Gold ◽  
Body Tissues ◽  
Research Findings ◽  
Cyclic Voltammetric Studies

In Modern medicine, metals and alloys are being used as implants. The Corrosion behaviour of various biomaterials under artificial body fluids are being studied. Artificial biomaterials are being implanted inside the human body to replace bone, teeth, etc. Even organs are being medically substituted with different types of metals such as mild steel, carbon steel, Ni-Cr alloy, Fe-Cr alloy, 22 carat Gold,24 carat Gold Tin, etc. due to their biocompatibility. This is achieved by connecting these metals directly with body tissues. The metals tend to corrode when it gets in contact with human body fluids. The body fluids thereby come in direct contact with tissues and the tissues are in contact with the metal thus causing the metal to corrode. And hence the corrosion resistance studies such as polarisation, AC impedance, cyclic voltammetric studies, etc, are being conducted in a medium like artificial blood plasma, artificial urine, artificial salvia, artificial sweat, Hank solution, Ringer solution, etc. The different body fluids are examined in the presence of different implantation metals by electrochemical methods and protective films are formed which are analyzed by various surface analysis techniques such as AFM, FTIR-UV, SEM, etc. The research findings will thereby be very helpful to the medical field.

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