Wireless Body Area Networking: Joint Physical-Networking Layer Simulation and Modeling

An electronic device equipped with sensors and antennas is the main part of the wireless body area networking (WBAN). Such a device is placed near human body and it usually works in a populated environment with many surrounding objects (e.g., building walls). The human body and the objects can change the radiation characteristics of the antenna and impact the performance of the wireless communication system. The wireless communication system’s performance is also affected by the networking layers established on top of the physical layer. Therefore, any designing method for WBAN application should be pervasive, offering a joint physical-networking layer simulation and modeling strategy. To this end, in this chapter, a comprehensive simulation and modeling method is presented. First, antenna design limitations and challenges for wireless body area networking are studied with emphasis on evaluating the antenna’s performance near the human body. Then, the antenna miniaturization techniques to reduce the antennas’ dimension are reviewed. Later, a system level analysis and modeling are used to study short-range communication between the wearable antennas with remote nodes using IEEE 802.11g wireless networking protocol

Modelling and characterisation of antennas and propagation for body-centric wireless communication

PhDBody-Centric Wireless Communication (BCWC) is a central point in the development of fourth generation mobile communications. The continuous miniaturisation of sensors, in addition to the advancement in wearable electronics, embedded software, digital signal processing and biomedical technologies, have led to a new concept of usercentric networks, where devices can be carried in the user’s pockets, attached to the user’s body or even implanted. Body-centric wireless networks take their place within the personal area networks, body area networks and body sensor networks which are all emerging technologies that have a broad range of applications such as healthcare and personal entertainment. The major difference between BCWC and conventional wireless systems is the radio channel over which the communication takes place. The human body is a hostile environment from radio propagation perspective and it is therefore important to understand and characterise the effect of the human body on the antenna elements, the radio channel parameters and hence the system performance. This is presented and highlighted in the thesis through a combination of experimental and electromagnetic numerical investigations, with a particular emphasis to the numerical analysis based on the finite-difference time-domain technique. The presented research work encapsulates the characteristics of the narrowband (2.4 GHz) and ultra wide-band (3-10 GHz) on-body radio channels with respect to different digital phantoms, body postures, and antenna types hence highlighting the effect of subject-specific modelling, static and dynamic environments and antenna performance on the overall body-centric network. The investigations covered extend further to include in-body communications where the radio channel for telemetry with medical implants is also analysed by considering the effect of different digital phantoms on the radio channel characteristics. The study supports the significance of developing powerful and reliable numerical modelling to be used in conjunction with measurement campaigns for a comprehensive understanding of the radio channel in body-centric wireless communication. It also emphasises the importance of considering subject-specific electromagnetic modelling to provide a reliable prediction of the network performance

Wideband and UWB antennas for wireless applications. A comprehensive review

A comprehensive review concerning the geometry, the manufacturing technologies, the materials, and the numerical techniques, adopted for the analysis and design of wideband and ultrawideband (UWB) antennas for wireless applications, is presented. Planar, printed, dielectric, and wearable antennas, achievable on laminate (rigid and flexible), and textile dielectric substrates are taken into account. The performances of small, low-profile, and dielectric resonator antennas are illustrated paying particular attention to the application areas concerning portable devices (mobile phones, tablets, glasses, laptops, wearable computers, etc.) and radio base stations. This information provides a guidance to the selection of the different antenna geometries in terms of bandwidth, gain, field polarization, time-domain response, dimensions, and materials useful for their realization and integration in modern communication systems

Characterisation of human body and environmental effects on the performance of mobile terminal antennas

PhDProvision of efficient services to the user anywhere at anytime is being a centre of research and development in Wireless Personal Area Networks (WPAN) and Wireless Body Area Networks (WBAN). Antenna is the essential part of WPAN/WBAN applications that got affected by two major factors: human body presence and nature of the surrounding environment. The presence of the human body in the proximity of the antenna causes electromagnetic (EM) reflections from the body surface and absorptions in the lossy body tissues resulting in antenna detuning, radiation pattern degradations and impedance mismatch. On the other hand, incident radio waves undergo reflections, difractions and scattering from the surrounding environment objects including buildings, trees, vehicles and ground, causing multipath fading. The thesis gives an overview of the main investigations, results and analyses accomplished in a study concerning the commercially available Bluetooth and GPS antennas working in the vicinity of the human body. Detailed numerical modelling process is adopted followed by measurements for validation. The thesis highlights the role of surface waves as a potential transmission medium in an on-body Bluetooth wireless communication link taking into account the effects of antenna-body separations and presence of the surrounding objects blocking the direct communication path. The thesis also presents a novel statistical model to evaluate the performance of GPS mobile terminal antennas in the multipath environment. This model characterises the antenna performance and identifies the key factors that can be used to enhance it, in a real working environment outside an anechoic chamber. The study also deals with presence of the human body in the multipath environment and its effects on the operation of the GPS antennas

Lessons Learned about the Design and Active Characterization of On-Body Antennas in the 2.4 GHz Frequency Band

This work addresses the design and experimental characterization of on-body antennas, which play an essential role within Body Sensor Networks. Four antenna designs were selected from a set of eighteen antenna choices and finally implemented for both passive and active measurements. The issues raised during the process of this work (requirements study, technology selection, development and optimization of antennas, impedance matching, unbalanced to balanced transformation, passive and active characterization, off-body and on-body configurations, etc.) were studied and solved, driving a methodology for the characterization of on-body antennas, including transceiver effects. Despite the influence of the body, the antennas showed appropriate results for an in-door environment. Another novelty is the proposal and validation of a phantom to emulate human experimentation. The differences between experimental and simulated results highlight a set of circumstances to be taken into account during the design process of an on-body antenna: more comprehensive simulation schemes to take into account the hardware effects and a custom design process that considers the application for which the device will be used, as well as the effects that can be caused by the human body.Ministerio de Economía y Competitividad (Instituto de Salud Carlos III) PI15/00306Junta de Andalucía PIN-0394-2017Unión Europea "FRAIL

인체통신용 안테나에 관한 연구

학위논문 (박사)-- 서울대학교 대학원 : 전기·컴퓨터공학부, 2015. 2. 남상욱.This thesis presents the antennas for in-body, on-body communication. The antennas in body communication are severely affected by human body which has a high relative permittivity and conductivity. The high relative permittivity and conductivity degrades the antenna bandwidth and efficiency. Therefore, it is a main challenge that enhancing the bandwidth and the efficiency of the antenna maintaining the small size. In order to enhance the performance of the antennas several techniques are proposed in body communication antennas. Firstly, the Q value and the efficiency of the in-body antenna are investigated. Using the proposed equations, the optimum frequency of the in-body antenna will be given. To maximize the antenna dimensions in the endoscopy antenna, the outer wall loop antennas is proposed. The measurement results are given to show the performance of the proposed antenna. Secondly, the several techniques for on-body antenna are proposed. The conventional antennas without the ground plane like dipole and slot antennas are not appropriate for on-body environment because the body has low intrinsic impedance and high conductivity compared to that of the free space. Therefore, antennas with ground plane like patch and cavity-backed slot antennas are proposed for on-body communication. The cavity-backed slot antenna with via-hole above the slot is proposed for bandwidth enhancement of the antenna. As the place of the via-hole introduces the additional resonance, wider bandwidth is achieved. The substrate removal technique for cavity-backed slot antenna is also proposed for the bandwidth and the efficiency enhancement. The removal of the substrate across the slot decreases the Q of the antenna, increasing the bandwidth and efficiency. In addition, the folded-cavity-backed slot antenna is given for size miniaturization of the cavity-backed slot antenna. The folded structure of the proposed antenna increases the effective length of the antenna, decreasing the antenna resonance frequency. Furthermore, the reconfigurable shorted patch antenna is given for wide bandwidth. Lastly, the dual-band and dual-impedance cavity-backed slot antennas are given for the efficient on-body systems1. Introduction 1 1.1 WBAN (Wireless Body Area Network) Applications 1 1.2 Electrical Properties of Human Body 5 1.3 Challenges in Designing Body Communication Antenna 7 2. Antennas in Human Body 10 2.1 Properties of the Antenna in Human Body 10 2.1.1 Radiation efficiency of the Antenna in Human Body 11 2.1.2 Q of the Antenna in Human Body 14 2.1.3 Numerical Results and Conclusion 15 2.2 Outer-Wall Loop Antenna for Capsule Endoscope System 18 2.2.1 Introduction 18 2.2.2 Antenna Design 20 2.2.3 Simulation and Measurement results 23 2.2.4 Conclusion 31 3. Antennas on human body 32 3.1 Properties of the Antenna on Human Body 32 3.1.1 Model of the Human Body 32 3.1.2 Antennas without Ground on Human Body 34 3.1.3 Antennas with Ground Plane on Human Body 36 3.2 Cavity-backed slot Antenna on Human Body 38 3.2.1 Operation of Cavity-backled Slot Antenna 38 3.2.2 Bandwidth and Efficiency Enhancement using Substrate Removal 40 3.2.3 Bandwidth Increase using Via-hole above the Slot 54 3.2.4 Miniaturization using Folded Cavity Structure 66 3.2.5 Dual-band Technique for Slot Antennas 81 3.2.6 Dual Impedance Cavity-backed Slot Antenna 86 3.3 Shorted Patch Antenna on Human Body 97 3.3.1 Operation of Shorted Patch Antenna 98 3.3.2 Reconfigurable Shorted Patch Antenna 100Docto

Design, Analysis and Applications of Wearable Antennas: A Review

Wearable antennas are the vital components for Body Centric Communication (BCC). These antennas have recently gained the attention of researchers and have received a great deal of popularity due to their attractive characteristics and opportunities. They are fundamental in the Wireless Body Area Networks (WBANs) for health care, military, sports, and identification purposes. Compared to traditional antennas, these antennas work in close proximity to the human body, so their performance in terms of return loss, gain, directivity, bandwidth, radiation pattern, efficiency, and Specific Absorption Rate (SAR) is influenced by the coupling and absorption of the human body tissues. Additionally, in the design of these antennas, size, power consumption, and speed can also play a paramount role. In most cases, these antennas are integrated into the clothes, or in some cases, they may be fixed over the skin of the users. When these characteristics are considered, the design of wearable antennas becomes challenging, particularly when textile materials are examined, high conductivity materials are used during the manufacturing process, and various deformation scenarios have an impact on the design’s performance. To enhance the overall performance of the wearable antennas and to reduce the backward radiation towards the human body, metamaterial surfaces are introduced that provide a high degree of isolation from the human body and significantly reduce the SAR. This paper discusses the state-of-the-art wearable/textile/flexible antennas integrated with metamaterial structures composed of wearable/flexible substrate materials, with a focus on single and dual band antenna designs. The paper also reviews the critical design issues, various fabrication techniques, and other factors that need to be considered in the design of wearable/textile/flexible antennas. All the designs presented in this work are of the recent developments in wearable technology

A Comprehensive Review of Wearable Antenna Design for On-Body and Off-Body Communication

Today age of advancement one of the fastest growing fields of the technology is wearable electronics and device. In the recent advancement the wearable devices for on and off body communication is going expeditiously. For the wearable wireless communication, wearable antennas are mostly used due to its compact size, self powered, light weight, low profile, portable wireless communication and sensing. This paper throws light on wearable antennas for on body and off body communication including their applications, advantages and disadvantages. A comparative study is conducted on designing of different on body and off body wearable antennas and parameters of designed antenna such as their size, shape, gain, SAR have been compared and analyzed. In this paper also discussed the impact of the wearable antenna on human body and impact of human body on antenn