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 flexible 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 operation. 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.     

A Review of Implant Intra-Body Communication

With an extending life expectancy and demand for medical healthcare, there are widespread and stringent requirements of implantable medical devices (IMDs) development for diagnostics, treatments, and therapies by emerging technologies. One of the primary targets for the IMDs is evolving a reliable, speed, and accurate communication method to provide proactive wellness management and thereby achieve early detection, disease prevention, and even treatments. Intra-body communication (IBC) is a potential technology envisioning a sensors/actuators network within a human body, which uses the conductive properties of a body and is categorized in the standardized IEEE 802.15.06 protocol. In the present review, the current state-of-art of implant intra-body communication has been surveyed. Based on the propagation mechanisms over investigated IBC spectrum (i.e., 0.1 MHz –100 MHz), the capacitive and galvanic coupling IBC is considered, where the subfields regarding modeling method (including circuit, numerical, analytical, and filter model), measurement details (including the effect of the electrode, cable, impedance, and instrument), clinical application (including cardiac pacemaker and wireless endoscope), transceiver design (including discrete component and CMOS technology) and media access control (MAC) layer design have been introduced or discussed. Furthermore, the open challenges and issues have been explored as an anticipated inspiration for future development.     

毫米波相阵多径信道中的迭代波束成形方法

因毫米波阵列阵元数量较多,在多径信道下波束成形向量算法一般具有较高的复杂度．提出了一种多径信道下基于毫米波相阵的低复杂度迭代波束成形方法．该方法首先在通信中的一端通过级数方法获得适用于毫米波相阵的波束成形向量;然后通过收发双方的相互迭代从而获取另一端的波束成形向量,在相互迭代过程中算法得到收敛．仿真结果表明,该方法能够获得较高的信道容量,从而实现高速率传输,在迭代3次左右后算法得到收敛,减小了链路建立过程中的开销．     

Ultra-Low Power Small Size 5.8.GHz RF Transceiver Design for WiMAX/4G Applications

A state of the art ultra-low power small sized transceiver design has been proposed. This device consists of four blocks, including a frequency synthesizer (FS), a crystal oscillator (XO), transmitter and receiver attached with an antenna. It has been seen that wireless information technology and systems have played a vital role in the transformation of society in different aspects of life. Mobile wireless communications including WiMAX/4G have attracted researchers and developers. WiMAX/4G applications need a transceiver that can be used in the worst channel conditions, but with low power consumption and low input voltage at the 5.8 GHz frequency. The proposed transceiver operates on 1.2 V. The operating frequency, noise figure (NF) and receiver gain are 5.8 GHz, 4.0 dB and 90 dB respectively. It is a highly compatible transceiver with all the 4 G technologies. Implementation details and results have revealed that the proposed transceiver is much more efficient than the previously proposed transceivers in literature.     

人体静电放电模拟引爆瓦斯的研究

煤矿环境中,矿工在狭窄坑道出口处人体电容迅速降低至原来电容的十分之一,人体动态电压会增加十几倍,容易成为瓦斯燃爆的点火源.通过对人体静电泄漏规律的分析得出:静电半衰期主要与介质的电阻率有关.通过人体静电放电模拟引爆瓦斯的实验,获得了不同的人体电容、放电间隙和瓦斯体积分数与瓦斯爆炸之间的关联.     

Body area communication based on quasi-electrostatic field and spread spectrum

Based on the electrical model of body area communication,the change tendency of channel gain in 100kHz-10MHz band was experimentally analyzed and verified.Results show that channel gain was flat and signal attenuation was approximately 43dB in 1MHz-10MHz band.The characteristics of the channel were taken into account in the design of body area spread spectrum communication and its multiuser receiver issue.BER-Eb/No curves of single user and multiuser were derived by simulation.The characteristics of body area commutation channel were studied and the feasibility of introducing spread spectrum theory to body area communication was verified.     

宽带卫星ATM网络及关键技术研究

作为一种新型的宽带卫星通信系统，卫星ATM网络将卫星通信和ATM技术的优势相结合，具有宽带、高比特率，能满足多媒体业务需求以及可灵活分配带宽等特点。由于ATM技术在有线网络中的应用基础是在高速率、低误码率的光纤信道中使用，因而在卫星环境下采用ATM技术将面临一系列特殊问题。在介绍卫星网络特点的基础上，着重讨论了目前卫星ATM网络的关键技术，如网络结构、轨道和频段、卫星点波束覆盖、卫星链路的多址方式、差错控制技术以及调制解调技术等，并对各个环节中常使用的技术进行了分析，比较各自的优缺点，从而得到最适合ATM卫星传输模式的技术。     

体温研究的意义及现况

从体温诊断、医学临床中的人工体温(局部加热和冷却)和体温的测量与模拟等方面阐明了体温研究工作的进展.     

A Modeling Method of the IBC System Based on the Composite Fading Channel

Intra-body communication (IBC) is a novel short-range non-RF(radio frequency) wireless communication technique specified by the IEEE 802.15.6 using the human body as a transmission medium. In this work, a new modeling method of the IBC system based on the composite fading channel is proposed, where the cascaded filter is used to express the composite fading channel and the modulation method in transmitter and receiver. The composite fading channel combines with the average attenuation, group delay, multipath effect, and shadowing effect. The modulation is adopted orthogonal frequency division multiplexing (OFDM), and thereby the constellation, cyclic prefix, bit error rate, and pilot mode are determined. As a result, the whole process and multi-parameter simulation of IBC system can be achieved. It provides a theoretical foundation for the system design of the intra-body communication and will promote its application to the wireless body area network (WBAN).     

Research on Dynamic Model of the Human Body

After summarizing the current situation of the research on human body modeling, a new dynamic model containing 5 equivalent masses has been proposed and the corresponding dynamic equations has been deduced too. By using this new model, more detailed information about the situation of the human body under impact and vibration can be obtained. The new model solves the problem that transmission functions of forces inside the human body can‘t be deduced by using 3-equivalent-mass model. It will find its usage in many applications.     

空间激光通信光端机发展水平与发展趋势

激光通信技术和传统通信技术相比具有极大的优越性和广阔的应用前景,其中光端机是实现空间激光通信的核心系统.论述了近年来发达国家在光端机研发方面所取得的成果,讨论了光端机研发的发展趋势.在未来多型平台之间进行组网激光通信的背景下,对光端机上一对多通信光学天线的各种设计方案进行了梳理,从几个方面评价了各种设计方案的优缺点,并对网络化通信的光学天线关键技术提出了一些新的思考和分析.     

基于小波变换的人体图像边缘检测

根据人体图像的特点 ,利用三次样条二进小波 ,采用Mallat快速算法进行小波分解 ,提取了人体图像的正面和侧面边缘 .结果显示 ,提取图像的边缘连续性较好 ,弯曲部分边缘也能准确提取 ,为人体着装图像的边缘检测提供一种新的方法     

Small MEMS smart antenna for software radio fuze

The signal transceiver of the software radio fuze depends on the front-end radio frequency (RF) antenna. RF micro-electro-mechanical-system (MEMS) smart antennas have the capability of flexible beam rapid scanning, multi-beam forming and so on, which can improve the ability of detecting, sensing and tracking multiple targets of the fuze. The small RF MEMS smart antenna consists of a 2×2 aperture coupled antenna array and six 1-bit MEMS phase shifters. Simulated results demonstrate that the antenna can complete beam steering angles of ±30° in both X and Y plane at 17.3.GHz. All components can be fabricated and monolithically integrated with MEMS technology which causes the system low cost and small volume. The RF MEMS smart antenna presents a good and important prospect for the development of the software radio fuze antenna.     

基于物联网络的无线智能消防炮控制系统

针对现有智能消防炮控制系统通过总线通信实现主、从机间的数据传送存在的通信距离短和受现场复杂环境限制的问题,设计了一种基于物联网络的无线消防炮控制系统。该系统在硬件上主要采用STM8S单片机和433M无线射频模块分别作为主控制器和无线数据收发器,软件上采用主机和从机间的安全认证协议和防碰撞协议算法。对该系统进行通信距离、防碰撞和安全认证测试,结果表明该系统通信距离远、误码率低、多机通信可靠。该系统已成功运用于消防改造项目中。     

基于支持向量机的多种人体姿态识别

为了实现对边防哨所等场合中无人监控的车辆、人体直立、哈腰、匍匐几种姿态的识别,提出了一种基于支持向量机的多种人体姿态识别方法.在对各种目标建立了样本库之后,提取了形状复杂性、矩形度、宽高比、头部矩形度等特征,利用支持向量机具有全局最优性和较好泛化能力的特点,进行了小样本的2类及多类目标分类识别,并和RBF神经网络的分类效果进行对比.实验结果表明,SVM不需进行网络迭代训练,求解速度明显高于RBF神经网络,且识别性能也优于RBF神经网络,并且采用径向基核的SVM性能最好.该方法识别率高,平均可达到96%,快速性好,识别速度平均为0.0172S,为小样本下的多目标分类及识别提供了理论和技术基础.     

伪随机序列快速跳频频率合成器的研制

军用跳频通信系统为了提高抗干扰能力和达到高的通信性能,要求跳频频率合成器具有高的跳频速度、低的相位噪声和杂散电平,同时输出频率按照伪随机序列跳变.本文介绍了一种伪随机序列快速跳频频率合成器.本跳频频率合成器采用直接数字频率合成技术(DDS)和锁相频率合成技术(PLL)相混合的形式产生高精度、高稳定的频率输出.该频率合成器的输出频率按m序列快速跳变,输出信号带宽为:350～510MHz,相位噪声优于-90dBC/Hz/1KHz,杂散电平优于-60dB.该频率合成器能应用于军用跳频通信系统,改善通信系统的抗干扰能力.     

基于Web技术的通信数据动态交互控制系统设计

为提升通信数据动态交互控制能力,降低信道的冲激响应时延和通信误码率,设计基于Web技术的通信数据动态交互控制系统。构建通信数据动态交互的信道传输模型,采用扩频序列重组方法实现通信数据动态交互过程中的信道均衡控制,在输出端不断调整增益实现通信数据动态交互的自适应均衡控制,采用Web技术实现通信数据动态交互控制过程中的自适应调节和组网控制,实现动态交互系统优化设计。仿真结果表明,与基于低密度奇偶校验码的控制系统、基于频分复用的控制系统相比,设计系统的信道的冲激响应时延和输出误码率更低,具有较好的通信数据动态交互控制能力。     

13.56MHz RFID读卡器天线的设计

简要介绍了由13.56 MHz射频芯片MFRC500设计的RFID读卡器,重点论述该读卡器天线的设计与实现.经实践证明,该天线具有良好的性能,使用该天线的阅读器工作稳定.     

Scheme for antenna design used in in-band full-duplex communication

In order to effectively suppress the self-interference of the in-band full-duplex communication system, a solution for designing the transceiver antenna based on the simple ring structure and collinear dipole is proposed. In this design, two printed dipole antennas are placed in the zero radiation direction of each other to achieve low port isolation between the two transceiver antennas. Then a simple ring structure is added to improve the isolation between the two antennas. Experimental results show that the two transceiver antennas designed by this scheme have omnidirectional radiation characteristics and can obtain a high port isolation of better than 45.9 dB in 2.4~2.6 GHz band. The scheme for designing the transceiver antenna proposed in this paper can not only effectively reduce the interference between two transceiver antennas, but also provide omnidirectional signal coverage. It is an effective solution for designing transceiver antennas for the in-band full-duplex communication system.     

基于LabVIEW的HDLC协议收发器设计

HDLC协议以其优异的性能在可靠性需求较高的场合得到了广泛应用.针对航天某领域的协议测试评估需求,解决传统协议测试设备程序复杂、开发周期长的问题.为了满足系统快速集成、协议参数灵活配置的总体要求,提出了一种基于LabVIEW软件构建HDLC协议收发器的方案,完成了HDLC核心收发模块设计,并以此为基础组成一套完整的测试系统.对HDLC协议处理及接收、发送程序设计进行了说明,着重介绍了收发器中核心循环校验码(CRC)校验模块及比特插入删除模块的实现方法,同时对收发器的主要功能模块进行了仿真和测试.使用LabVIEW设计的HDLC收发器轻量高效、运行灵活,可应用于HDLC协议设备的测试和协议性能分析等场合,提高数据通信系统的扩展性、实时性和稳定性.