Ultra-Wideband Log Periodic Dipole Antenna (LPDA) for Wireless Communication Applications

This paper proposes a printed log-periodic dipole antenna (LPDA) for ultra wide bandwidth (UWB) applications. The antenna comprises of cascading four U shaped elements of different line lengths with balun circuit to improve the antenna impedance matching. The proposed antenna dimensions are 50 × 50 mm2 with FR4 substrate thickness 0.8 mm. Full-wave EM solver HFSS (High Frequency Structure Simulator) is used for modeling the proposed antenna. The pulse distortion is verified by the measured the proposed antenna performance with virtually steady group delay. The simulation and experimental results show that the proposed antenna exhibits good impedance matching, stable radiation patterns throughout the whole operating frequency bands, acceptable gain and stable group delay over the entire operating band. An UWB extended from 1.85 GHz to 11 GHz is obtained, and the average antenna gain is about 5.5 dBi over the operating band with peak gain around 6.5 dBi and 70% average radiation efficiency.

基于TOF和自适应抗差卡尔曼滤波的UWB室内定位算法

为提高超宽带(UWB)定位系统在室内复杂环境下的定位精度,提出一种基于飞行时间(TOF)和自适应抗差卡尔曼滤波(ARKF)的改进定位算法。针对超低功耗宽带设备在复杂室内环境状态下易受周围干扰而存在标准时间偏差的问题,提出一种改进的TOF算法,同时进行测距标定,拟合数据;对室内存在非视距(NLOS)干扰的情形,提出一种ARKF算法,通过比较残差与3倍信息的方差来判断视距(LOS)与NLOS情形。实验结果显示:该算法可以在静态与动态定位实验中有效提高系统定位精度,降低定位误差,取得较好的定位效果。

基于UWB的天然气站场室内三维定位系统研究

为解决天然气站场室内定位中因非视距(NLOS)现象导致人员和设备定位精度低的问题,设计了一种基于超宽带(UWB)与Three.js的天然气站场室内人员与设备三维定位系统。通过B/S三层架构,以Django框架和VUE框架为基础,利用Python、HTML5、CSS3和Three.js,实现定位信息在网页客户端的三维可视化。通过对UWB技术的研究,为保证定位精度,基于到达时间差(TDOA)测量值,采用卡尔曼滤波算法对其进行NLOS滤波,并结合Chan算法融合多基站数据,最终得到目标点的计算位置。通过搭建实验环境,对三维定位系统进行定位标签静态和动态定位实验。实验结果表明,对于NLOS现象严重的复杂室内环境,该系统定位精度高、运行平稳,能为天然气站场室内定位提供一种切实可行的技术。

PDR与UWB融合的森林消防员定位系统设计

针对森林消防员在林区环境下由于全球导航卫星系统(GNSS)定位拒止及惯性导航误差累积而难以精确定位的问题,设计了一种融合行人航位推算(PDR)和超宽带(UWB)测距的定位系统。首先,基于消防员个体装备的便携性要求,利用加速度计、磁强计、陀螺仪和气压计设计头戴式定位系统;其次,将指挥员作为基站,利用UWB测得消防员与基站之间的距离;接着,基于扩展卡尔曼滤波(EKF)设计了PDR与UWB融合的定位算法,将测距信息与消防员的运动状态进行融合解算,约束误差发散;最后,利用设计的软硬件定位系统进行了验证实验。结果表明:在真实林区实验中,与无约束PDR相比,采用PDR与UWB融合的定位方法将位置误差减小了60.04%,有效提升了系统的定位精度。

基于时频域特征融合的IR-UWB穿墙雷达人体行为识别方法

冲激脉冲(impulse radio,IR)超宽带(ultra-wideband,UWB)穿墙雷达因其良好的穿透性和距离分辨率在穿墙人体行为识别领域具有重要作用,但是常规识别方法仅采用单域特征对行为模式进行描述,识别准确率不高。针对这一问题,提出基于时频域特征融合的IR-UWB穿墙雷达人体行为识别算法。首先,通过杂波抑制及距离补偿方法获取高信噪比的人体行为距离像。其次,基于距离像提取目标时域特征,与频域特征进行融合,构建数据集。最后,基于支持向量机(support vector machine,SVM)算法对人体行为进行识别。实验结果表明,所提算法对于IR-UWB穿墙雷达人体行为识别能够达到95%的准确率。

MIMO Antenna for UWB Communications

Design of ultra-wideband antennas is challenging in the stringent requirements that are often conflicting to achieve a wide impedance bandwidth while maintaining high radiation efficiency, uniform gain and compact size. A Multiple-Input Multiple-Output (MIMO) antenna system can enhance the overall antenna performance but at having to overcome new challenges such as reducing the mutual coupling and the correlation between the elements. A printed circular disc compact planar antenna is selected in this work due to its UWB performance and compact size for the MIMO antenna system. A parametric analysis is carried out to achieve an optimal design. The system developed consists of two elements with an overall size of 59 × 27 mm. The designed antenna system operates over the whole of the UWB bandwidth from 3.1 to 10.6 GHz with radiation efficiency up to 85% and reflection coefficients less that ?10 dB. The envelope correlation is less than ?60 dB throughout the UWB band while the diversity gain approaches 10 throughout the entire UWB bandwidth and Total Active Reflection Coefficient (TARC) between the antenna elements is less ?11 dB. Thus the proposed MIMO antenna outperforms similar antenna systems reported in the literature.

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.

融合全局与局部特征的UWB雷达人体动作识别算法

为了消除雷达信号中杂波和噪声对人体动作识别的干扰,提高小样本数据下动作识别的精度,在去除杂波及噪声干扰的基础上,提出一种融合全局与局部特征的超宽带(ultra-wideband,UWB)雷达人体动作识别算法。用动目标指示(moving target indication,MTI)结合自适应中值滤波对雷达原始回波信号进行预处理,再对人体动作的雷达二维特征图像利用主成分分析(principal component analysis,PCA)提取主要分量作为全局特征表征,并用二维离散小波变换(2D discrete wavelet transform,2D-DWT)结合奇异值分解(singular value decomposition,SVD)获取特征图像在不同方向与尺度划分下动作的局部特征表征,并将全局与局部特征进行串联融合;根据融合特征,在网格搜索算法(grid search,GS)优化的支持向量机(support vector machines,SVM)模型中实现人体动作的识别分类。实验结果表明,该算法能有效获取雷达信号中的人体动作信息,平均识别准确率为95.63%,具有良好的识别性能。

利用科赫分形解耦的四端口紧凑型QSC UWB MIMO天线

提出一种利用共面波导(Coplanar Waveguide,CPW)馈电的四端口紧凑型准自互补(Quasi-self-complementary,QSC)超宽带(Ultra-Wideband,UWB)多输入多输出(Multiple-input Multiple-output,MIMO)天线。此UWB MIMO天线的整体尺寸为40 mm×30 mm×0.8 mm,由4个六边形准自互补辐射单元对称排列而成,印刷在介质板的一侧。介质板另一侧印刷科赫分形解耦枝节和新型正六边形双开口谐振环(double-split ring resonator,DSRR)阵列,分别提升低频和高频处天线单元间的隔离度。实验与测试结果表明,此天线的工作带宽为3.1 GHz~15.5 GHz,在大部分工作频段内,隔离度达到20 dB以上。此外,天线在整个工作频带内具有良好的辐射特性和稳定的增益。包络相关系数小于0.04,表明该天线能够很好地满足极化分集特性,可用于便携式UWB MIMO无线通信系统。

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.

A Novel Ultra-Wideband Monopole Antenna with Band-Stop Characteristic

In this letter, a simple monopole antenna with variable band-notched characteristic for ultra wide band (UWB) function is proposed. Two L-shaped quarter-waveguide resonators coupled to the ground plane with two shorting tracks at the sides of the antenna are used to generate stop-band performance around 5.5 GHz (WLAN). The proposed antenna is fabricated on the substrate FR4 (relative permittivity of 4.7) and has a compact size of 16 × 28.5 × 1.6 mm. The designed antenna has a good impedance matching in 3.1 - 11.4 GHz frequency range with VSWR < 2, except the band 5 - 5.85 GHz.

3 - 10 GHz Ultra-Wideband Low-Noise Amplifier Using Inductive-Series Peaking Technique with Cascode Common-Source Circuit

The objective of this paper is to investigate a ultra-wideband (UWB) low noise amplifier (LNA) by utilizing a two-stage cascade circuit schematic associated with inductive-series peaking technique, which can improve the bandwidth in the 3-10 GHz microwave monolithic integrated circuit (MMIC). The proposed UWB LNA amplifier was implemented with both co-planer waveguide (CPW) layout and 0.15-μm GaAs D-mode pHEMT technology. Based on those technologies, this proposed UWB LNA with a chip size of 1.5 mm x 1.4 mm, obtained a flatness gain 3-dB bandwidth of 4 - 8 GHz, the constant gain of 4 dB, noise figure lower than 5 dB, and the return loss better than –8.5 dB. Based on our experimental results, the low noise amplifier using the inductive-series peaking technique can obtain a wider bandwidth, low power consumption and high flatness of gain in the 3 - 10 GHz. Finally, the overall LNA characterization exhibits ultra-wide bandwidth and low noise characterization, which illustrates that the proposed UWB LNA has a compact size and favorable RF characteristics. This UWB LNA circuit demonstrated the high RF characterization and could provide for the low noise micro-wave circuit applications.

Ultra Wideband Microstrip Diamond Slotted Patch Antenna with Enhanced Bandwidth

An Ultra Wideband (UWB) microstrip diamond slotted patch antenna with enhanced bandwidth is presented in this paper. The proposed antenna is simulated in CST Microwave Studio and fabricated for measurements. Its simulated result displays impedance bandwidth from 3.28 GHz to 19.64 GHz, whereas the measured result displays the frequency region from 2.01 GHz to 18.67 GHz. The antenna complies with the return loss of S11 < –10 dB and Voltage Standing Wave Ratio (VSWR) < 2 throughout the impedance bandwidth. Details of the antenna design and related results such as phase angle, input impedance and radiation patterns are discussed in this paper. This antenna has surpassed the bandwidth of UWB requirement, which is from 3.1 GHz to 10.6 GHz, and exhibits good UWB characteristics.

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.

Experimental Study of On-Body Radio Channel Performance of a Compact Ultra Wideband Antenna

In this paper, on-body radio channel performance of a compact ultra wideband (UWB) antenna is investigated for body-centric wireless communications. Measurement campaigns were first done in the chamber and then repeated in an indoor environment for comparison. The path loss parameter for eight different on-body radio channels has been characterized and analyzed. In addition, the path loss was modeled as a function of distance for 34 different receiver locations for propagation along the front part of the body. Results and analysis show that, compared with anechoic chamber, a reduction of 16.34% path loss exponent is noticed in indoor environment. The antenna shows very good on-body radio channel performance and will be a suitable candidate for future efficient and reliable body-centric wireless communications.

利用UWB校正LiDAR SLAM的室内组合定位方法

针对室内定位中激光雷达(LiDAR)即时定位与地图构建(SLAM)算法误差会随时间累积以及超宽带(UWB)定位的结果较为分散的问题,提出了一种利用UWB观测值来校正LiDAR SLAM的组合定位方法。首先,通过里程计预测模型得到先验的位置估计信息;之后,利用粒子滤波融合LiDAR的观测值进行修正得到局部定位结果;最后,通过高斯滤波利用UWB观测值进行校正得到全局定位结果。实验结果表明:组合定位系统有效消除了LiDAR SLAM的累积误差,并且轨迹相对于UWB定位更为平滑。

Link Budget Design with Performance Evaluation of Tunable Impulse-Based Ultra Wideband to Support the Integration of Wireless Sensing and Identifications Infrastructures

Recently, many studies propose the use of ultra-wideband technology for passive and active radio frequency identification systems as well as for wireless sensor networks due to its numerous advantages. By harvesting these advantages of IR-UWB technology at the physical-layer design, this paper proposes that a cross layer architecture platform can be considered as a good integrator for different wireless short-ranges indoor protocols into a universal smart wireless-tagged architecture with new promising applications in cognitive radio for future applications. Adaptive transmission algorithms have been studied to show the trade-off between different specific QoS requirements, transmission rates and distances at the physical layer level and this type of dynamic optimization and reconfiguration leads to the cross-layer design proposal in the paper. Studies from both theoretical simulation and statistical indoor environments experiments are considered as a proof of concept for the proposed architecture.

Miniaturized Planar Ultra-Wideband Bandpass Filter with Notched Band

This paper presents a planar ultra-wideband (UWB) bandpass filter with sharp out-of-band rejection performance. The filter is formed by a folded multiple-mode resonator to realize high performance in an operation band from 3.3 to 10 GHz with a very compact size of 20 mm × 20 mm × 0.5 mm. An extra notched band centered at 5.8 GHz is further accomplished by etching a Hilbert fractal curve slit on the filter without the necessity of readjusting the geometrical parameters. The simulated and measured results are in good agreement.

UWB定位中基于XGBoost的NLOS识别方法

NLOS场景下UWB室内定位精度下降,识别出NLOS有助于进一步提升定位精度。针对超宽带定位中非视距识别的问题,提出基于XGBoost的NLOS识别方法。基于XGBoost决策树算法,采用两个层面的数据源对UWB定位中NLOS进行识别:元数据层面,用真实定位场景中采集的UWB CIR数据作为数据源;统计数据层面,将CIR数据经过一定的加工,得到几个关键的信号特征参数作为数据源。两组实验结果表明,XGBoost算法在元数据和统计数据上识别精确度分别达到91%和92%。UWB定位中XGBoost算法能显著提高识别NLOS信号的准确度。

Adaptive waveform design based on Morlet wavelet for ultra-wideband MIMO radar

For the issue of deterioration in detection performance caused by dynamically changing environment in ultra-wideband（UWB） multiple input multiple output（MIMO） radar, this paper proposes a novel adaptive waveform design which is aimed to improve the ability of discriminating target and clutter from the radar scene. Firstly, a sequence of Morlet wavelet pulses with frequency hopping and pulse position modulation by Welch-Costas array is designed. Then a waveform optimization solution is proposed which is achieved by applying the minimization mutual-information（MI） strategy. After that, with subsequent iterations of the algorithm, simulation results demonstrate that the optimal waveform design method brings an improvement in the target detection ability in the presence of noise and clutter.