MODIFIED ULTRA WIDEBAND CIRCULAR PRINTED MONOPOLE ANTENNA

A simple and compact microstrip-fed ultra wideband （UWB） printed monopole antenna is presented. The antenna is composed of a circular radiator and a finitely grounded plane. The antenna occupies about 16.62 GHz absolute bandwidth and 142.7% relative bandwidth covering from 3.38 GHz to 20 GHz with voltage standing wave ratio （VSWR） below two. A quasi-omnidirectional and quasi-symmetrical radiation pattern in H plane is obtained in the whole bandwidth. The high performance of the antenna is validated with measured and simulated results given. The antenna can be applied for the system design of UWB wireless communication.

Ultra-wideband bilateral tapered slot-line antenna fed by coplanar waveguide

In order to broaden the bandwidth of a tapered slot- line antenna （TSA）, a bilateral tapered slot-line antenna （BTSA） with a new feeding structure of coplanar waveguide （CPW） is developed. Based on the fact that the bandwidth limitation of TSA mainly depends on its feeding structure, an improved CPW-based feed structure etched on the backboard of the BTSA is adopted to perform traveling-wave transition. Both the simulation results and measurement data verify that the proposed feeding structure results in ＂high-pass＂ frequency response for antenna impedance matching. The voltage standing wave ratio （VSWR） is less than 2：1 when the frequency is higher than 3 GHz. The antenna gain exceeds 7 dBi with good radiation patterns when the bandwidth is from 4 to 16 GHz. This ultra wideband （UWB） antenna with a compact size is specially available for the electronic systems of counter-measure and microwave imaging.

Compact ultra-wideband monopole antenna with dual-band notched function

A kind of compact ultra wideband （UWB） monopole antenna with dual-band notched function is presented.The proposed antenna,using ＂C＂ and ＂L＂ apertures embedded in the annular ring patch and ground patch,gets two bandnotched characteristics in WiMAX3.5 GHz and WLAN 5.5 GHz.The size of antenna is 24 mm × 36 mm × 1.6 mm.The simulation results show that waveband range of the antenna is 2.7-10.6 GHz for S11 ＜-10 dB and the band-notched wavebands are 3.2-3.8 GHz and 5.1-6 GHz.So it has miniaturization,ultra-band and band-notched characteristics.Meanwhile,the radition pattern,directivety and gain are perfect,which meets the practical need.

Parametric estimation of ultra wideband radar targets

Based on the analysis of impulse response properties, a scattering model of ultra wideband （UWB） radar targets is developed to estimate the target parameters exactly. With this model, two algorithms of multiple signal classification （MUSIC）, and matrix pencil （MP）, are introduced to calculate the scattering center parameters of targets and their performances are compared. The simulation experiments show that there are no differences in the estimation precision of MUSIC and MP methods when the signal-to-noise ratio （SNR） is larger than 13 dB. However, the MP method has a better performance than that of MUSIC method when the SNR is smaller than 13 dB. Besides, the time consuming of MP method is less than that of MUSIC method. Therefore, the MP algorithm is preferred for the parametric estimation of UWB radar targets.

Design of ultra wideband microwave absorber effectual for objects of arbitrary shape

In this paper, we present the design of multilayer microwave absorbers comprised of Co Fe alloy nano-particles and nano-flakes as fillers. The thickness of the unite layer is optimized by using the Genetic Algorithm. Efficient microwave absorptions over a wide frequency band and a range of incident angles are achieved by using multilayer absorbers. We show that the absorbers are effective not only for a planar surface but also for arbitrarily shaped objects as well.

A NOVEL ULTRA WIDEBAND MONOPOLE ANTENNA WITH BAND-NOTCHED CHARACTERISTICS

A simple and compact microstrip-fed Ultra WideBand(UWB) printed monopole antenna with band-notched characteristic is proposed in this paper.The antenna is composed of a square ring with a small strip bar,so that the antenna occupies about 7.69 GHz bandwidth covering 3.11～10.8 GHz with expected band rejection from 5.12 GHz to 5.87 GHz.A quasi-omnidirectional and quasi-sym-metrical radiation pattern is also obtained.This kind of band-notched UWB antenna requires no ex-ternal filters and thus greatly simplifies the system design of UWB wireless communication.

Study of plasma-based stable and ultrawideband electromagnetic wave absorption for stealth application

A plasma-based stable,ultra-wideband electromagnetic（EM） wave absorber structure is studied in this paper for stealth applications.The stability is maintained by a multi-layer structure with several plasma layers and dielectric layers distributed alternately.The plasma in each plasma layer is designed to be uniform,whereas it has a discrete nonuniform distribution from the overall view of the structure.The nonuniform distribution of the plasma is the key to obtaining ultra-wideband wave absorption.A discrete Epstein distribution model is put forward to constrain the nonuniform electron density of the plasma layers,by which the wave absorption range is extended to the ultra-wideband.Then,the scattering matrix method（SMM） is employed to analyze the electromagnetic reflection and absorption of the absorber structure.In the simulation,the validation of the proposed structure and model in ultra-wideband EM wave absorption is first illustrated by comparing the nonuniform plasma model with the uniform case.Then,the influence of various parameters on the EM wave reflection of the plasma are simulated and analyzed in detail,verifying the EM wave absorption performance of the absorber.The proposed structure and model are expected to be superior in some realistic applications,such as supersonic aircraft.

基于硅基堆叠SIP技术的超宽带T/R组件

传统的超宽带T/R组件采用的是两维砖块式结构,体积和重量已不适应目前小型化、低剖面、易共形的相控阵天线要求。文中提出的基于硅基堆叠系统级封装(SIP)技术,将四通道的射频芯片高度集成在硅基介质基板上,将多层介质基板厚金压合,实现多层堆叠的三维封装。通过采用芯片多功能集成技术和超宽带射频信号的垂直互连技术,设计出三维堆叠的四通道超宽带T/R组件。T/R组件带宽为6 GHz~18 GHz,单通道的发射功率优于23 dBm,接收增益优于20 dB,可实现6位数控衰减及6位数控移相,尺寸仅有13.0 mm×13.0 mm×3.4 mm。该技术可以实现多通道超宽带T/R组件的SIP封装,有利于工程应用。

超宽带硅基射频微系统设计

针对超宽带硅基射频模块的微系统化问题,采用硅基板作为转接板设计了一款具备收发功能的超宽带系统级封装(System in Package,SiP)射频微系统。各层硅基转接板之间的射频信号传输、控制和供电等均采用低损耗的硅通孔(Through Silicon Via,TSV)结构来实现。为了减小封装对射频性能的影响,整个超宽带射频微系统采用5层硅基封装结构,与传统二维封装结构相比,其体积减少95%以上。射频微系统封装完成后,对其电气性能指标进行了测试。在整个超宽带频带内,其接收噪声系数小于2.6 dB,增益大于35 dB,发射功率大于等于34 dBm,端口驻波小于2。该封装结构实现了硅基超宽带射频模块的微系统化,可广泛适用于各类超宽带射频系统。

Closed BER expression of multi-user DS UWB systemsin indoor fading channel

The bit error rate （BER） performance of multi-user direct spreading bi-phase shift keying （DSBPSK） direct impulse ultra wideband （UWB） systems is analyzed and simulated based on a statistical indoor multi-path fading channel model. The BER of the system is theoretically derived and given in closed form, which is expressed in terms of channel parameters and system parameters such as pulse width parameter, pulse repeat period, user number and pulse waveform. With this BER expression, the effect of these parameters on the system performance can be evaluated in a uniform way. Simulation results well match the theory numerical results, and prove that the multi-access interference （MAI） of DS-BPSK UWB is a normal distribution.

基于TOA的迭代最小二乘定位算法研究

室内环境中基站与标签之间的距离会受到随机误差的影响,针对超宽带(UWB)系统的定位特性,提出了一种迭代加权最小二乘(IRLS)算法削弱测距随机误差的影响。首先,利用加权最小二乘算法获得标签的三维坐标。其次,通过构建中间变量,利用中间变量与位置坐标的关系构造迭代关系,并通过迭代计算提高标签三维坐标点位精度,得出最优解。仿真结果表明,在静态定位实验中,IRLS算法与经典最小二乘(LS)算法的平均点位误差分别为11.96 cm和13.42 cm,IRLS算法的定位结果优于LS算法;在动态定位实验中,经过卡尔曼滤波算法平滑处理后,IRLS算法的点位精度相比经典LS算法提升了12.82%。因此,IRLS算法可以显著提高UMB定位系统的点位精度。

A UWB/IMU-Assisted Fingerprinting Localization Framework with Low Human Efforts

With the rapid development of smart phone,the location-based services(LBS)have received great attention in the past decades.Owing to the widespread use of WiFi and Bluetooth devices,Received Signal Strength Indication(RSSI)fingerprintbased localization method has obtained much development in both academia and industries.In this work,we introduce an efficient way to reduce the labor-intensive site survey process,which uses an UWB/IMU-assisted fingerprint construction(UAFC)and localization framework based on the principle of Automatic radio map generation scheme(ARMGS)is proposed to replace the traditional manual measurement.To be specific,UWB devices are employed to estimate the coordinates when the collector is moved in a reference point(RP).An anchor self-localization method is investigated to further reduce manual measurement work in a wide and complex environment,which is also a grueling,time-consuming process that is lead to artificial errors.Moreover,the measurements of IMU are incorporated into the UWB localization algorithm and improve the label accuracy in fingerprint.In addition,the weighted k-nearest neighbor(WKNN)algorithm is applied to online localization phase.Finally,filed experiments are carried out and the results confirm the effectiveness of the proposed approach.

Multi-access performance of DS UWB systemunder indoor dense multi-path channel

The performance of multi-user code to direct spreading bi-phase shift keying （DS-BPSK） direct impulse ultra wideband （UWB） systems under indoor multi-user and multi-path environment is analyzed and simulated. The system output signals with Rake receiver are derived, then a simple and practical code selection scheme is given; i. e., with a large occupation to empty ratio of the repeating pulses, directly choosing those random or pseudo-random user codes with enough length and good co-relative orthogonal features will make the performance of DS-BPSK approximate the optimum and, so there is no need to carefully design the code or its type. The system multi-access performances are simulated using Gold sequence and PN codes as multi-user codes under CMI-CM4 multi-path channels. Simulation results prove that the proposed scheme is feasible.

50GHz~110GHz宽带信号下变频技术

矢量信号分析仪作为传统扫频式频谱仪与快速傅里叶变换技术的结合,能够对信号进行数字化处理,分析各种调制信号,同时获得测量信号的幅度和相位信息,对于现代通信意义重大。随着电磁波的应用频率扩展到毫米波乃至太赫兹波段,矢量信号分析仪的测量频率也急需拓展到更高频段,在系统前端搭载下变频器可实现这一目的。基于50GHz~110GHz宽带信号的下变频技术开展研究,研制了变频系统中多个关键器件,包括频分50GHz~110GHz信号的宽带开关、抑制镜频信号的宽阻带波导滤波器以及基于倍频放大模块的本振,同时搭建了50GHz~110GHz宽带信号下变频系统,将50GHz~110GHz宽带信号下变频到4.6GHz~39.6GHz。实验表明,下变频后的信号在任意2GHz内平坦度小于±3.5dB,对镜频信号的抑制大于60dBc,输出杂散抑制度大于40dBc,本振泄漏抑制大于70dBc,满足系统指标要求。

Novel band-notched UWB antenna for WUSB system

A simple and compact microstrip-fed ultra wideband （UWB） printed monopole antenna with band-notched performance is proposed for wireless universal serial-bus （WUSB）. The antenna is composed of a U-shaped line radiator and a small strip bar and is partially grounded, so that the measured impedance bandwidth of the antenna is about 7. 88 GHz covering 3. 12 to 11 GHz with VSWR below 2, and the expected band rejection of 5.06 to 5. 89 GHz is also obtained. The characteristics of the proposed antenna are analyzed, and the geometric parameters for optimal performance are investigated in detail. A relatively stable, quasi-omnidirectional and quasi-symmetrical radiation pattern is also found. The proposed band-notched UWB antenna requires no external filters to avoid interference with other systems, and thus, greatly simplifies the system design of an ultra wideband WUSB communication system.

带有NLOS误差补偿的UWB/INS室内融合定位算法研究

针对室内环境中超宽带(Ultra-Wideband,UWB)定位精度易受非视距影响,以及惯性导航系统(Inertial Navigation System,INS)误差随运行时间迅速累积的问题,在无迹卡尔曼滤波的基础上提出了一种带有非视距误差补偿的UWB/INS室内融合定位算法。该算法利用INS预测定位目标的位置信息;采用残差检验法对相邻时刻UWB测距结果进行非视距检测;利用INS预测信息设计了“近似补偿误差”,结合UWB测距信息实现对非视距测量值的误差补偿;利用无迹卡尔曼滤波算法以紧耦合方式融合UWB和INS定位信息,得到融合定位结果。实验结果表明,该算法既能抑制INS的误差累积,又能缓解非视距误差对UWB定位技术的影响,具有较好的定位精度和鲁棒性。

基于物联网超宽带无轨胶轮车运输定位系统的研究与应用

传统的无轨胶轮车调度管理方式已经难以应对现代化工业企业生产运输的实际需求。从智能化角度出发,在物联网超宽带技术的基础上研究无轨胶轮车智能化运输定位系统,并从硬件和软件两方面进行设计,利用MATELAB进行模拟分析,验证系统应用可行性,最后将其应用于某工业企业运输工作当中,分析系统应用的经济性。

基于超宽带技术的运动目标跟踪高精度定位系统设计

为克服运动目标不断变化导致跟踪定位精度较低的问题,设计基于超宽带技术的运动目标跟踪高精度定位系统;图像采集模块由FPGA单元、VGA显示单元、帧缓存单元以及图像采集单元构成,以此实现运动目标跟踪与定位中的图像采集,在超宽带技术模块中,设计超宽带运动目标定位所需的天线、定位基站、移动节点,完成超宽带动态组网,实现硬件系统的设计;基于硬件系统采集到的图像,实施图像灰度化处理、形态学滤波处理,以增强图像中有用的信息,设计TLD运动目标跟踪算法,随着运动目标开始运动,TLD模型会不断学习跟踪的运动目标,获取目标在距离、景深、角度等层面的改变,并不断学习、识别,达到良好的跟踪效果,基于超宽带技术设计运动目标动态定位算法,依据跟踪结果实现运动目标的高精度定位,完成软件系统的设计;实验测试结果表明,该系统在中、远距离目标跟踪与定位实验中跟踪错误率低于0.60%、2.4%,沿着S型运动时,路线弯折处的定位误差较低,与实验运动目标的飞行路线相贴合,具有良好的定位能力。

Performance analysis of an indoor UWB ranging system

To evaluate the ranging performance of impulse radio ultra wideband （IR-UWB） signals, an experiment is performed in a typical indoor environment. In order to mitigate the ranging error caused by theoretical algorithm and practical circuits, one way-time difference of the arrival （OW-TDOA） ranging method and corresponding approaches are proposed and carried out according to the structure of UWB transceivers. Generalized maximum likelihood （GML） estimator based on energy detection is applied for the time of arrival estimation. The obtained results show that this UWB ranging system can achieve a relative high ranging accuracy in a multipath environment （e.g. about 5 cm at ranges up to 6 m）, which is practical and meaningful for many sensor applications.

Virtual fire drill system supporting co-located collaboration

Background Due to the restriction of display mode,in most of the virtual reality systems with multiple people in the same physical space,the program renders the scene based on the position and perspective of the one user,so that other users just see the same scene,resulting in vision disorder.Methods To improve experience of multi-user co-located collaboration,in this study,we propose a fire drill system supporting co-located collaboration,in which three co-located users can collaborate to complete the virtual firefighting mission.Firstly,with multi-view stereoscopic projective display technology and ultra wideband(UWB)technology,co-located users can roam independently and watch virtual scenes through the correct perspective view based on their own position by wearing dedicated shutter glasses,thus carrying out different virtual tasks,which improves the flexibility of co-located collaboration.Secondly,we design simulated firefighting water-gun using the micro-electromechanical system sensor,through which users can interact with virtual environment,and thus provide a better interactive experience.Finally,we develop a workbench including a holographic display module and multi touch operation module for virtual scene assembly and virtual environment control.Results The controller can use the workbench to adjust the virtual layout in real time,and control the virtual task process to increase the flexibility and playability of system.Conclusions Our work can be employed in a wide range of related virtual reality applications.