Anti-interference ultra-wideband system based on spreading and interleaving

To suppress the interference in the ultra-wideband （AI-UWB） system is a challenging problem. An anti-interference multiband orthogonal frequency-division multiplexing ultra-wideband （AI-UWB） system, based on spreading and interleaving is addressed. It will exploit the frequency diversity across the subcarriers and provide the robustness to narrow-band interference, by spreading the coded bit streams within each sub-band and interleaving across all sub-bands. Simulating results show that the spreading and interleaving provide about 5 dB to 10 dB advantages over the conventional multiband orthogonal frequency-division multiplexing ultra-wideband system in signal-to-interference ratio. Spreading and interleaving is an effective cure for enhancing the robustness to narrowband interference.

Chaotic pulse position modulation ultra-wideband system based on particle filtering

Traditional chaotic pulse position modulation(CPPM)system has many drawbacks.It introduces delay into the feedback loop,which will lead to divergence of chaotic map easily.The wrong decision of data will cause error propagation.Mismatch of parameters and synchronization error between the receiver and transmitter will arouse high bit error rate.To solve these problems,a demodulation algorithm of CPPM based on particle filtering is proposed.According to the mathematical model of the system,it tracks the real signal by online separation in demodulation.Simulation results show that the proposed method can track the true signal better than the traditional CPPM scheme.What's more,it has good synchronization robustness,reduced error propagation by wrong decision and low bit error rate.

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。

Ultra-Wideband Electromagnetic Radiation from GaAs Photoconductive Switches

The experiment results of ultrawide band electromagnetic radiation with DC biased GaAs photoconductive semiconductor switch combining double ridge horn antenna triggered by high repeat frequency femto-second laser pulse are reported.The GaAs switches are insulated by solid multi-layer transparent dielectrics and the distance of two electrodes is 3mm.The electrode material of the switch is ohmic contact through alloy technics with definite proportion of Au/Ge/Ni.This switch and double ridge horn antenna are integrated and the receive antenna is connected with the test instrument.From receiving antenna,ultra fast electrical pulse of 200ps rise time and 500ps pulse width is obtained,the repetition rate of the pulse is about 82MHz and the frequency spectrum is in the range of 4.7MHz～14GHz.The radiation characteristic of the ultrafast electrical pulse is analyzed.

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。

In Situ Atomic Reconstruction Engineering Modulating Graphene-Like MXene-Based Multifunctional Electromagnetic Devices Covering Multi-Spectrum

With the diversified development of big data,detection and precision guidance technologies,electromagnetic(EM)functional materials and devices serving multiple spectrums have become a hot topic.Exploring the multispectral response of materials is a challenging and meaningful scientific question.In this study,MXene/TiO_(2)hybrids with tunable conduction loss and polarization relaxation are fabricated by in situ atomic reconstruction engineering.More importantly,MXene/TiO_(2)hybrids exhibit adjustable spectral responses in the GHz,infrared and visible spectrums,and several EM devices are constructed based on this.An antenna array provides excellent EM energy harvesting in multiple microwave bands,with|S11|up to−63.2 dB,and can be tuned by the degree of bending.An ultra-wideband bandpass filter realizes a passband of about 5.4 GHz and effectively suppresses the transmission of EM signals in the stopband.An infrared stealth device has an emissivity of less than 0.2 in the infrared spectrum at wavelengths of 6-14μm.This work can provide new inspiration for the design and development of multifunctional,multi-spectrum EM devices.

Maximum Correntropy Criterion-Based UKF for Loosely Coupling INS and UWB in Indoor Localization

Indoor positioning is a key technology in today’s intelligent environments,and it plays a crucial role in many application areas.This paper proposed an unscented Kalman filter(UKF)based on the maximum correntropy criterion(MCC)instead of the minimummean square error criterion(MMSE).This innovative approach is applied to the loose coupling of the Inertial Navigation System(INS)and Ultra-Wideband(UWB).By introducing the maximum correntropy criterion,the MCCUKF algorithm dynamically adjusts the covariance matrices of the system noise and the measurement noise,thus enhancing its adaptability to diverse environmental localization requirements.Particularly in the presence of non-Gaussian noise,especially heavy-tailed noise,the MCCUKF exhibits superior accuracy and robustness compared to the traditional UKF.The method initially generates an estimate of the predicted state and covariance matrix through the unscented transform(UT)and then recharacterizes the measurement information using a nonlinear regression method at the cost of theMCC.Subsequently,the state and covariance matrices of the filter are updated by employing the unscented transformation on the measurement equations.Moreover,to mitigate the influence of non-line-of-sight(NLOS)errors positioning accuracy,this paper proposes a k-medoid clustering algorithm based on bisection k-means(Bikmeans).This algorithm preprocesses the UWB distance measurements to yield a more precise position estimation.Simulation results demonstrate that MCCUKF is robust to the uncertainty of UWB and realizes stable integration of INS and UWB systems.

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。

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。

Progress in ultra-wideband planar antennas

This paper introduces the advances of ultra-wideband （UWB） and super-wideband （SWB） planar antennas based on the printed monopole, microstrip slot and other planar antenna designs in the last decade. A brief history of the ultrawideband antennas is first provided. Several types of planar antennas for UWB systems with band-notched designs are reviewed. Special SWB planar antenna designs with the bandwidth ratio greater than 10：1 including metal-plate and printed monopole antennas and tapered slot antennas are presented and compared.

Ultra-wideband reflective polarization converter based on anisotropic metasurface

In this paper, we propose an ultra-wideband reflective linear cross-polarization converter based on anisotropic metasurface. Its unit cell is composed of a square-shaped resonator with intersectant diagonal and metallic ground sheet separated by dielectric substrate. Simulated results show that the converter can generate resonances at four frequencies under normal incident electromagnetic（EM） wave, leading to the bandwidth expansion of cross-polarization reflection. For verification,the designed polarization converter is fabricated and measured. The measured and simulated results agree well with each other, showing that the fabricated converter can convert x- or y-polarized incident wave into its cross polarized wave in a frequency range from 7.57 GHz to 20.46 GHz with a relative bandwidth of 91.2%, and the polarization conversion efficiency is greater than 90%. The proposed polarization converter has a simple geometry but an ultra wideband compared with the published designs, and hence possesses potential applications in novel polarization-control devices.

Ultra-wideband printed antennas for communication applications

A new type of ultra-wideband （UWB） printed monopole antennas is presented, which is composed of a circular or armular patch and a trapeziform ground plane with a tapered CPW feeder in the middle. Both simulated and experimental results are presented, showing good agreement and therefore verifying validity of the design. The proposed antenna with a circular monopole patch achieves an 11.6： 1 measured ratio bandwidth of VSWR ≤2 （ from 0,79 GHz to 9.16 GHz）, while that with an annular patch obtains a measured ratio impedance bandwidth of 10.6：1 （from 0.87 GHz to 9.47 GHz）. In addition, these designs exhibit nearly omnidirectional radiation patterns with simple compact structures, which axe attractive in communications and others UWB applications.

Human Respiration Rate Estimation Using Ultra-wideband Distributed Cognitive Radar System

It has been shown that remote monitoring of pulmonary activity can be achieved using ultra-wideband (UWB) systems, which shows promise in home healthcare,rescue,and security applications.In this paper,we first present a multi-ray propagation model for UWB signal,which is traveling through the human thorax and is reflected on the air/dry-skin/fat/muscle interfaces,A geometry-based statistical channel model is then developed for simulating the reception of UWB signals in the indoor propagation environment.This model enables replication of time-varying multipath profiles due to the displacement of a human chest.Subsequently, a UWB distributed cognitive radar system (UWB-DCRS) is developed for the robust detection of chest cavity motion and the accurate estimation of respiration rate.The analytical framework can serve as a basis in the planning and evaluation of future rheasurement programs.We also provide a case study on how the antenna beamwidth affects the estimation of respiration rate based on the proposed propagation models and system architecture.

Ultra-wideband circular-polarization converter with micro-split Jerusalem-cross metasurfaces

An ultrathin micro-split Jerusalem-cross metasurface is proposed in this paper, which can efficiently convert the linear polarization of electromagnetic （EM） wave into the circular polarization in ultra-wideband. By symmetrically employing two micro-splits on the horizontal arm （in the x direction） of the Jerusalem-cross structure, the bandwidth of the proposed device is significantly extended. Both simulated and experimental results show that the proposed metasurface is able to convert linearly polarized waves into circularly polarized waves in a frequency range from 12.4 GHz to 21 GHz, with an axis ratio better than 1 dB. The simulated results also show that such a broadband and high-performance are maintained over a wide range of incident angle. The presented polarization converter can be used in a number of areas, such as spectroscopy and wireless communications.

Photonic generation of power-efficient FCC-compliant ultra-wideband waveforms using semiconductor optical amplifier (SOA):theoretical analysis and experiment verification

We theoretically design a power-efficient ultra-wideband pulse generator by combining three monocycle pulses with different weights. We also experimentally demonstrate a feasible scheme to generate such power-efficient ultra-wideband waveforms using cross-phase modulation in a single semiconductor optical amplifier. The designed ultra-wideband pulse fully satisfies the requirements for the spectral mask specified by the Federal Communications Commission with high power efficiency. In the experiment, a power-efficient ultra-wideband waveform with a pulse duration of 310 ps is achieved, and the power efficiency is greatly improved compared with that of a single nlonocycle pulse or a mixture of two monoeycles.

Study on the Generation of Ultra-Wideband (UWB) High Power Microwave

The experimental study of ultra-wideband (UWB) technology, its generation and on-line measurement are presented. An experimental repetitive UWB system is designed, manufactured, and tested. High-pressure spark gap switch and its components, as well as oil spark gap switch are studied experimentally on the system. Experimental results indicate that the system operates at a 200 pps repetitive rate with a stable performance. 100 MW peak power UWB pulses are obtained on the system. Fast-time response capacitive divider is designed and fabricated, allowing for an accurate measurement of the high power UWB signal. The main issues related to the design of the switch and the UWB signal online measurement are discussed.

Differential multiuser detection using a novel genetic algorithm for ultra-wideband systems in lognormal fading channel

We employ a multiuser detection (MUD) method using a novel genetic algorithm (GA) based on complementary error function mutation (CEFM) and a differential algorithm (DA) for ultra-wideband (UWB) systems.The proposed MUD method is termed CEFM-GA DA for short.We describe the scheme of CEFM-GA DA,analyze its algorithm,and compare its computational complexity with other MUDs.Simulation results show that a significant performance gain can be achieved by employing the proposed CEFM-GA DA,compared with successive interference cancellation (SIC),parallel interference cancellation (PIC),conventional GA,and CEFM-GA without DA,for UWB systems in lognormal fading channel.Moreover,CEFM-GA DA not only reduces computational complexity relative to conventional GA and CEFM-GA without DA,but also improves bit error rate (BER) performance.