A 2Mbps Human Body Communication Transceiver Based on Body Antenna Effect

This paper presents a human body communication(HBC)transceiver for wireless body network applications.The transceiver employs on frequency shift keying(FSK)modulation and op-erates in 40 MHz-60 MHz which is the resonant frequency of the human body as an antenna.It achieves high performance and stability through establish passive microstrip line and via models and active device-models.The proposed transceiver is designed and fabricated by FR4 printed cir-cuit board(PCB)process,the transceiver has the ability of configurable data rate up to 2 Mbps and it achieves-86 dBm receiving sensitivity at 2 Mbps data rate.Meanwhile,the transceiver out-put power dynamics range is 34 dB.Furthermore,with a visual interaction interface,the transceiv-er can be agility use in a variety of scenarios.Its measurements are verified on human body.The result shows that the transceiver has ability to send data from person to person by relying on hu-man body antenna radiation.The transceiver shows great prospect in wireless body area networks(WBAN)for telemedicine and emergency communication.

Analysis of wave propagation on human body based on stratified media model

Human body communication(HBC) is a promising near-field communication(NFC) method emerging in recent years. But existing theoretical models of HBC are too simple to simulate the wave propagation on human body. In this work, in order to clarify the propagation mechanism of electromagnetic wave on human body, a surface waveguide HBC theoretical model based on stratified media cylinder is presented. A numerical model analyzed by finite element method(FEM) is used for comparing and validating the theoretical model. Finally, results of theoretical and numerical models from 80 MHz to 200 MHz agree fairly well, which means that theoretical model can characterize accurate propagation mechanism of HBC signal. Meanwhile, attenuation constants derived from two kinds of models are within the range from 1.64 to 3.37, so that HBC signal can propagate effectively on human body. The propagation mechanism derived from the theoretical model is useful to provide design information for the transmitter and the modeling of the propagation channel in HBC.

Low Power Single-Chip RF Transceiver for Human Body Cormunication

Human body communication is proposed as a promising body proximal comanunication tech- nology for body sensor networks. To achieve low power and slmll volume ill the sensor nodes, a Ra-dio Frequency （RF） application-specific integrated circuit transceiver tbr Human Body Commnunication （HBC） is presented and the characteristics of HBC are investigated. A high data rate On-Off Keying （OOK）/Frequency-Shift Keying （FSK） modulation protocol and an OOK/FSK delrodulator circuit are introduced in this paper, with a data-rate-to-carrier-frequency ratio up to 70%. A low noise amplifier is proposed to handle the dynamic range problem and improve the sensitivity of the receiver path. In addi-tion, a low power autonmatic-gain-control system is realized using a novel architecture, thereby render-ing the peak detector circuit and loop filter unneces-sary. Finally, the complete chip is fabricated. Simula-tion results suggest receiver sensitivity to be-75 dBm. The transceiver shows an overall power con-smxption of 32 mW when data rate is 5 Mbps, de-livering a P1dB output power of - 30 dBm.

A Novel Flexible Antenna at Very High Frequency Band for On-Body Applications

This paper proposes a novel flexible antenna design operating at very high frequency(VHF)band for on-body applications such as human body communication(HBC).The antenna consists of back-to-back E-shaped fractal and complimentary structures designed over a thin flex-ible substrate.The overall design working on the principle of fractal geometries and capacitive coupling is highly beneficial to achieve better antenna characteristics even at low frequencies around 35 MHz-45 MHz that are being used for HBC application.The proposed antenna obtained a large bandwidth of around 10.0 MHz in air and a bandwidth of around 8.0 MHz during on-body opera-tion.The antenna has been tested in three different scenarios viz.air,on-body single antenna and on-body communication using two antennas.The insertion loss is reduced to a minimum in all three scenarios,which is quite beneficial for better signal transmission.The size miniaturization with high flexibility in such low frequencies has also been achieved in the paper that makes the proposed design suitable for human body communication applications.

个体差异性对人体通信信道特性的影响研究

不同人体间的差异对以人体为通信介质的无线通信技术的实际应用存在影响。现有关于人体通信(HBC)技术的研究对人体差异性考虑不多。首先,根据体质指数(BMI)建立超重、标准和偏瘦3种体质模型,设置以左胸为发射机的5条通信链路;然后,分析了男女在不同体质下的信道传输特性;最后,计算了不同模型在不同频段下的比吸收率(SAR)。结果表明:超重或偏瘦都会增大路径损耗;偏瘦女性模型的多径数目多于超重模型;偏瘦和超重男性模型在5条链路的多径数目趋势类似;电磁波信号在女性模型传输时产生的多径数目多于男性;SAR在不同模型也有不同的规律。研究人体差异性对通信信道的影响,为HBC技术更好的应用奠定了基础。

可穿戴设备中基于人体通信的身份识别方法研究

针对目前生物识别技术在穿戴式设备上应用的缺陷,提出一种可应用于可穿戴设备上的生物识别方法。利用300 k Hz^1.5 GHz的电磁波在人体通信信道传输中产生的幅度衰减特性曲线作为生物特征。为了验证此方法的可行性,首先,利用矢量网络分析仪测量生物特征;其次,提取数据的梯度,使用支持向量机进行分类器模型训练和测试。验证结果与直接对采集的生物特征进行分析的方法对比,引入梯度的分析方法使得正确识别率从90.45%提高到94.54%,等错误率从0.95%降低到0.14%,接收者操作特征曲线下面积从0.997 1增加到0.999 9。因此,基于人体通信的身份识别方法可为穿戴式设备的身份认证系统研究提供一种方法。

人体通信信道测试系统的研究与实现

人体通信以人体为通信媒介,具有低功耗、高速率、高安全性等优点,其为人体传感器网络提供了一种理想的通信方式。设计了一种人体通信信道测试系统,具有"浮地"特性,能真实反映人体通信的耦合或感应机制。该系统采用ARM7TDMI内核的S3C44B0X系统作为开发平台,使用直接数字合成器(DDS)芯片AD9910设计可调频率信号源,使用对数放大器芯片AD8310设计信号强度检测器。测试结果表明:可调频率信号源频率范围为0～200MHz,窄带无杂散动态范围大于80dB;信号强度检测器检测分辨率可达0.1 dB。该系统采用电池供电,成功地在电磁屏蔽室做大量实验,并测试得到人体信道特性。

人体通信频段体内至体表信道特性分析与建模

为探究人体通信(HBC)频段体内无线通信系统的传输特性,该文对解剖学数值人体模型和多层异质几何人体模型的体内至体表信道特性进行电磁仿真分析,首次建立了人体通信频段内10~50 MHz体内至体表路径损耗模型,并通过生物液态仿体内测量验证了电磁仿真和路径损耗模型的有效性。首先,结合时域有限积分法和数值人体模型计算10~50 MHz人体心脏节点至体表各节点的平均路径损耗,分析对比解剖学数值人体模型和多层异质人体模型的路径损耗、阴影衰落和电磁场分布特性。其次,基于表面波传播机理,提出一个带有线性修正项的对数路径损耗模型,最后建立完整的10~50 MHz体内至体表植入式人体信道模型。仿真分析和实验结果表明,该文提出的带有线性修正项的路径损耗模型可以更准确地描述此频段体内至体表路径损耗特性,采用解剖学数值人体模型进行此频段信道建模与特性研究可以有效提高植入式信道模型的可靠性。

基于不同路径长度的人体通信信号传输检测方法研究

为了研究了人体通信(HBC)中信号传输检测与通信链路路径长度的关系,在同一人体模型下检测了不同链路的信号传输特性与传输链路路径长度的关系(横向检测分析);考虑到信号在人体表面非直线传播的特性,通过设置对照组,检测了不同身高人体模型下信号发射端传感器和接收传感器位置相对一致的链路,研究了其信道传输特性与通信链路路径长度的关系(纵向检测分析)。通过横向和纵向的比较,说明在HBC频段,路径长度对人体通信信号传输特性有一定影响,即随着传输链路路径长度的增大,信号传输的路径损耗增大。另外,检测表明这种关系在信号非直线传播的情况下也成立。

基于多姿势人体模型的信道研究

基于人体的多姿势模型进行仿真研究,以观察姿势变化对人体的动态影响。同时提取多姿势中的幅值及时间参数进行分析,以详细分析姿势会产生影响的原因。结果表明:人体动作会对路径增益产生影响,这种变化并不会影响信道稳定性,大幅度动作具有更好的传输效率。人体多姿势的变化带来的不同信道增益遵循正态分布,可将姿势的影响认为是乘以变化的统计随机量。而路径的到达时间与路径距离成正相关,多姿势下模型仿真的多路径叠加还会出现为新的巅峰值,实务中须对此加以考虑。

双人通信的动态信道特性分析

人体通信是以人体生物组织为传输介质的新型短距离通信技术,现有人体通信技术的相关研究局限于单人通信。基于此,研究了低频段下双人动态通信的传输特性,在通过手臂接触进行双人通信的情况下,首先分析了非接触手臂沿着垂直人体的方向,向前和向后运动对通信信道特性的影响;在非接触手臂运动的情况下,发射端放置在接触手臂或非接触手臂时,其各自对应的2条通信链路的路径损耗变化趋势几乎一样;利用二阶信息准则判定多径信号中第一径到达时间的累计概率密度符合Weibull分布;最后对比了发射端在不同位置下的通信特性,在手臂发生运动的情况下,发射端放置在双人接触手臂时的链路通信效果较好且对人体辐射较小。