Ultra-wide band gap and wave attenuation mechanism of a novel star-shaped chiral metamaterial

A novel hollow star-shaped chiral metamaterial(SCM)is proposed by incorporating chiral structural properties into the standard hollow star-shaped metamaterial,exhibiting a wide band gap over 1500 Hz.To broaden the band gap,solid single-phase and two-phase SCMs are designed and simulated,which produce two ultra-wide band gaps(approximately 5116 Hz and 6027 Hz,respectively).The main reason for the formation of the ultra-wide band gap is that the rotational vibration of the concave star of two novel SCMs drains the energy of an elastic wave.The impacts of the concave angle of a single-phase SCM and the resonator radius of a two-phase SCM on the band gaps are studied.Decreasing the concave angle leads to an increase in the width of the widest band gap,and the width of the widest band gap increases as the resonator radius of the two-phase SCM increases.Additionally,the study on elastic wave propagation characteristics involves analyzing frequency dispersion surfaces,wave propagation directions,group velocities,and phase velocities.Ultimately,the analysis focuses on the transmission properties of finite periodic structures.The solid single-phase SCM achieves a maximum vibration attenuation over 800,while the width of the band gap is smaller than that of the two-phase SCM.Both metamaterials exhibit high vibration attenuation capabilities,which can be used in wideband vibration reduction to satisfy the requirement of ultra-wide frequencies.

ON THE PAR REDUCTION OF MB-OFDM ULTRA-WIDEBAND SIGNALS

The Peak to Average power Ratio (PAR) of a Multi-Band Orthogonal Frequency-Division Multiplexing (MB-OFDM) Ultra-Wide Band (UWB) signals can be substantially larger than that of single carrier or carrier-less ultra-wideband signals. In this letter, a novel PAR reduction scheme for the MB-OFDM UWB system based on spreading and interleaving is proposed. By spreading the coded bits over each subcarrier in corresponding band and interleaving the spread symbols across all bands, the PAR statistics of the MB-OFDM signals can be improved and the PAR is reduced obviously. In the PAR reduction scheme, there is no loss in transmission data rate or Bit Error Rate (BER) performance decreasing. Since the spreading and interleaving operation are implemented by unitary Hadamard sequences and used for an approach to provide the robustness of the UWB system to narrowband interference, there is no additional implementation burden. Simulation results show that the investigated scheme gives the PAR reduction of 3dB compared with that of the original MB-OFDM signals.

Compact Coplanar Epsilon-Negative Antenna with Ultra-Wide Band Character

In this paper, a compact coplanar epsilon.negative(ENG) antenna is proposed with ultra.wide operation band and small size of 18×11.5 mm2. The proposed antenna is designed based on a coplanar.waveguide(CPW) feeding antenna, and thus the via.free structure is employed to realize the ENG unit cell, which is convenient to tune the frequency of zeroth.order resonance(ZOR) and extends the ZOR bandwidth. The high.order resonant frequencies are achieved and mainly determined by the separate slots that are located between the radiating patch and the ground plane. Adding the left.handed inductance between the radiating patch and ground has slight impact on the high.order resonant frequencies, and then the ultra.wide band is achieved by merging the ZOR bandwidth with the high.order resonant bandwidths. The ground plane primarily works as a matching network for the proposed antenna. Although it generates a low.frequency resonance, the performance is undesirable due to the impedance mismatching. The measured results show that the reflection coefficient, |S11| <.10 d B, is in a wide frequency range from 5.25 to 13 GHz, which covers the upper operation band of UWB communication. Also, the antenna contains relatively stable gains and omni.directional radiation patterns.

Fully-integrated ultra-wide band LNA in 0.18μm CMOS technology for 3-10 GHz applications

The paper presents a fully integrated ultra-wide band(UWB)low noise amplifier(LNA)for 3-10 GHz applications.It employs self-biased resistive-feedback and current-reused technique to achieve wide input matching and low power characteristics.An improved biased architecture is adopted in the second stage to attain a better gain-compensation performance.The design is verified with TSMC standard 1 P6 M 0.18μm RF CMOS process.The measurement results show that the parasitic problem of the transistors at high frequencies is solved.A high and flat S21 of 9.7±1.5 dB and the lowest NF 3.5 dB are achieved in the desired frequency band.The power consumption is only 7.5 mA under 1.6 V supply.The proposed LNA achieves broadband flat gain,low noise,and high linearity performance simultaneously,allowing it to be used in 3-10 GHz UWB applications.

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.

Mobile Robot Positioning and Tracking Based on Ultra-wideband Technology

To solve the precision self-positioning problem for mobile robot,a positioning program based on ultra-wideband technology was proposed. Ultra-wideband pulse has very high bandwidth; ranging accuracy can achieve centimeter-level theoretically. The mobile robot obtained the distance to the reference node by sending ultra-wideband pulse. According to the geometric relations among the references and the robot,establish equations to calculate the position coordinates. Then Kalman filter algorithm was applied for mobile robot tracking. Simulation results show that robot positioning and tracking based on ultra-wideband technology can achieve indoor and outdoor seamless docking.

Designing a Carbon Nanotube Field-Effect Transistor with High Transition Frequency for Ultra-Wideband Application

Theoretical calculations predict transition frequencies in the terahertz range for the field-effect transistors based on carbon nanotubes, and this shows their suitability for being used in high frequency applications. In this paper, we have designed a field-effect transistor based on carbon nanotube with high transition frequency suitable for ultra-wide band applications. We did this by optimizing nanotube diameter, gate insulator thickness and dielectric constant. As a result, we achieved the transition frequency about 7.45 THz. The environment of open source software FETToy is used to simulate the device. Also a suitable model for calculating the transition frequency is presented.

Numerical simulation of the coupling of ultra-wide band electromagnetic pulse into landmine by aperture

The modern landmine＇s electronic fuse is susceptible to strong interference or can even be damaged by the ultra-wide band electromagnetic pulse（UWB-EMP）. The finite-difference time-domain（FDTD） method in lossy media with cylindrical coordinates is used to study the interactions of the UWB-EMP with the landmine. First, the coupling of UWB-EMP into the landmine shielding shell through an aperture is numerically simulated. Second, the coupled electromagnetic field of mine shells made of different shielding materials and with apertures of different sizes is plotted. Third, the aperture coupling laws of UWB-EMP into shells are analyzed and categorized. Such an algorithm is capable of effectively preventing ladder similar errors, and consequently improving the calculation precision, and in addition to adopting the message passing interface（MPI） parallel method to divide the total calculating range into more sub-ranges, the overall calculating efficiency is greatly increased. These calculations are surely a constructive reference for modern landmine design against electromagnetic damage.

Evaluation of System Performance of Ultra-Wide Band Jointing in MC Signaling in Correlated Environments

The evaluation of System Performance of UWB (ultra-wide band) jointing in MC (multi-carrier) signaling in correlated environments is presented in the report. The correlated Nakagami-m statistical distribution for the multipath fading model is assumed in this scenario. In fact to establish the model for analyzing in this article is using MC-CDMA (multi-carrier code-division multiple-access) system characterization combined with a UWB scheme. The average BER (bit error rate) is calculated and compared to a special case of previously published results. Studied results from this paper can be implied to approve the system performance for a UWB system combined with a MC-CDMA wireless communication system. It is worth noting that the Nakagami-m distributed fading parameter significantly dominates UWB system performance when it cooperates with MC signaling under a fading environment. Finally, it is worthy of noting that when the SNR (signal-to-noise ratio) at system’s receiver reaches a preset high threshold value, the parameter of power decay ratio effect could be not included.

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.

一种复杂环境下UWB测距误差预测方法

针对复杂室内环境中,多径干扰和视距遮挡影响室内定位精度的问题,提出一种复杂环境下UWB测距误差的预测方法:根据超宽带(UWB)室内定位方法抗干扰能力强、定位精度高的特点,从理论上分析影响超宽带信号测距精度的因素;然后通过模型量化分析每种影响因素对测距误差的影响程度,改进以往通过信道脉冲响应特征分析单一的视距遮挡参数来提高定位精度的补偿算法;最后从数据挖掘和机器学习的角度出发,将多径效应、视距遮挡、标签与基站的距离、标签移动速度、标签与基站天线俯仰角以及气象因素(温度、湿度、压强)等对测距精度造成影响的重要因素作为特征进行分类和归类,并使用梯度提升决策树模型对数据集进行训练和预测。实验结果表明,该模型可以根据当前状态下的组合特征值估计出测距误差值,将当前预测的误差值补偿到测量值上,可以有效提高超宽带室内定位的精度。

Miniaturized Novel UWB Band-Notch Textile Antenna for Body Area Networks

This paper presents the design and analysis of a miniaturized and novel wearable ultra-wideband(UWB)band-notch textile antenna for Body Area Networks(BANs).The major goal of building the antenna for wearable applications with band notch in X-band is to reject the downlink band(7.25 to 7.75 GHz)of satellite communication in the UWB frequency ranges of 3.1–10.6 GHz to keep away from interference.Computer Simulation Technology(CST)TM Microwave Studio,which is user-friendly and reliable,was used to model and simulate the antenna.The radiating element of the antenna is designed on Jeans’textile substrate,which has a relative permittivity of 1.7.The thickness of the jeans’fabric substrate has been considered to be 1 mm.Return loss,gain,bandwidth,impedance,radiation,and total efficiency,and radiation patterns are presented and investigated.The antenna is simulated placed on the three layers of the human body model,and the on-body results are summarized in comparison with free space.Results and analysis indicate that this antenna has good band-notch characteristics in the frequency range of 7.25 GHz to 7.75 GHz.The parametric study varying the relative permittivity of Jeans’fabric substrate of this antenna is also evaluated.In addition,effects on the antenna parameters of variation of ground plane size have been reported.The antenna is 25 mm×16 mm×1.07 mm in total volume.Results reveal that this antenna achieves the design goal and performs well both in free space and on the body.

High Gain UWB Four Elements Antenna Array for C-Band and X-Band Application

The C-band is allocated for commercial telecommunications via satellites. Amateur satellite operations in the frequency range 5.830 to 5.850 GHz for down-links and 5.650 to 5.670 GHz for up-links are allowed by International Telecommunication Union. The X-band is used for terrestrial broadband communication, radar applications, and portions of the X-band are assigned for deep space telecommunications. In this paper, a design of 4 × 1 Ultra Wide Band (UWB) antenna array for C-band and X-band applications is introduced. Metamaterial sixteen-unit cells are incorporated into each antenna element for radiation characteristics enhancement purposes. Permeability and permittivity of metamaterial unit cells are obtained all over the operating bandwidth. UWB unequal power divider is used to feed the proposed four elements antenna array based on Chebyshev excitation method. The proposed antenna has a suitable 3 dB beam width and gains all over the operating bandwidth which extends from 5.6 GHz to 10.9 GHz. The proposed antenna covers 60% and 72.5% of the C-band and X-band, respectively. The proposed antenna is fabricated, measured, and good agreement is obtained between simulated and measured results. The obtained performance ensures the suitability of the proposed antenna array for C-band and X-band applications.

Optimization of band-notched UWB antenna using micro-genetic algorithm combined with FDTD

The micro-genetic algorithm (MGA) optimization combined with the finite-difference time-domain (FDTD) method is applied to design a band-notched ultra wide-band (UWB) antenna. A U-type slot on a stepped U-type UWB monopole is used to obtain the band-notched characteristic for 5 GHz wireless local area network (WLAN) band. The measured results show that voltage standing wave ration (VSWR) less than 2 covers 3.1-10.6 GHz operating band and VSWR more than 2 is within 5.150-5.825 GHz notched one with the highest value of 5.6. Agreement among the calculated, HFSS simulated and measured results validates the effiectiveness of this MGA-FDTD method, which is efficient for UWB antennas design.

Compact Bluetooth/UWB Antenna with Multi-Band Notched Characteristics

A small-sized, low-profile, and planar dual band antenna for Bluetooth (2.4 - 2.484 GHz) and ultra-wideband (UWB) (3.1 - 10.6 GHz) with multi-band notched antennas is presented. Two antennas A and B with different types of slots are used to obtain tri-band notched characteristic. In antenna A notched bands, 5 - 6 GHz for WLAN, and 3.3 - 4 GHz for WiMAX, are achieved using a U-slot in ground structure and in the radiating patch. In antenna B two notched bands at 3.3 - 4 GHz, for WiMAX and 7.2 GHz for C-band satellite communication systems are achieved by using a U-slot in ground structure and a H-shaped slot in the radiating patch. The radiation characteristics of the two antennas are calculated using a commercial EM simulator based on Finite Element Method (FEM) and the Finite Integration Technique (FIT). The two antennas show acceptable gain flatness with stable omnidirectional radiation patterns across the integrated Bluetooth and UWB bands.

A Novel Bow-Tie Antenna with Triple Band-Notched Characteristics for UWB Applications

This paper presents the design of a compact bow-tie antenna with triple band notched characteristics for UWB applications. The proposed antenna can operate from 3.1 to 10.6 GHz with VSWR - 8.4 GHz) centered at 8.1 GHz, the CSRR2 rejects the WLAN band (5.15 - 5.85 GHz) centered at 5.6 GHz, and the CSRR3 rejects the band (4.10 - 4.47 GHz) centered at 4.32 GHz. Compared with recent design, this antenna is more compact, and presents better simulation results of its characteristics. Our newly designed antenna is a potential candidate for application in UWB communication systems.

基于UWB定位技术的煤矿机械装备防碰撞系统研究

随着煤矿机械装备的广泛应用,机械装备的防碰撞已经成为煤炭行业重要的研究课题。文章主要研究了基于超宽带(Ultra Wide Band,UWB)定位技术的煤矿机械装备防碰撞系统,通过开发定位算法、防碰撞算法、数据处理与分析等功能模块,实现系统的实时监控与报警功能。实验表明,该系统能够有效避免机械装备之间发生碰撞,进而提升煤矿生产的安全性。

基于Taylor-Chan算法的改进UWB室内三维定位方法

[目的]针对室内三维空间环境复杂导致传统超宽带(ultra wide band,UWB)定位算法精度低、稳定性差的问题对UWB室内三维定位方法进行研究.[方法]在Chan和Taylor算法基础上,设计了一种基于距离误差筛选机制的Taylor-Chan定位算法.首先使用简化Taylor算法求解得到标签初定位结果,再结合初定位结果和测距信息根据所设计筛选函数剔除误差较大的基站数据,最后基于筛选得到的数据,使用Chan算法得到最终标签定位结果.[结果]在室内视距和非视距两种场景下进行仿真,Taylor-Chan算法相比于Chan和Taylor定位精度都有一定的提高,且测距误差越大的情况下,Taylor-Chan算法的定位效果越明显.[结论]仿真结果表明,对比现有方法,本文所提出的Taylor-Chan算法在室内三维空间的视距和非视距环境下都能有效改善定位精度.

改进抗差卡尔曼滤波的UWB定位模型

针对超宽带(UWB)技术已在室内定位、智能交通等领域广泛应用,但由于障碍物遮挡或其他原因,使得UWB测距值可能存在误差,从而大幅度降低UWB的定位精度和可靠性的问题,分析抗差卡尔曼滤波(RKF)在UWB定位中的特点,在此基础上,提出改进的RKF算法(RKF-SW)进行粗差检测,根据预测残差进行第一次样本异常值检验探测,采用1/4样本分位数进行第二次样本异常值探测。实验结果表明,与RKF算法相比,RKF-SW算法具有较强的异常值识别能力,能够提升UWB系统的定位精度,开阔场景下定位精度可提高约80.0%,遮挡物干扰情况下可提高约82.1%。

New band-notched UWB antenna

A simple and compact ultra wideband （UWB） printed monopole antenna with band-notched performance is proposed in this paper. The antenna is partially grounded so that the Q value is depressed and the impedance bandwidth is broadened. A small strip bar is loaded on each arm of the similar U-shaped radiator. The impedance bandwidth of the antenna overlap with IEEE 802.11a is rejected consequently. The geometry parameters of the antenna are investigated and optimized with HFSS. The measured bandwidth of the proposed antenna occupies about 7.89 GHz covering from 3.05 GHz to 10.94 GHz with expected notched band from 4.96 GHz to 5.98 GHz. A quasi-omnidirectional and quasi-symmetrical radiation pattern in the whole band is also obtained. As a result, a UWB wireless communication system can be simplified with the band-notched UWB antenna presented.