面向复杂机房环境的室内定位技术应用研究#br#

考虑到机房数据中心运维智能化管理迫切需要精准的室内定位服务,针对机房金属遮挡、电磁辐射和其他机房设备干扰严重的复杂环境以及非视距传播误差显著降低传统室内定位精度问题,提出一种运用最优化理论原理和K最邻近算法的抗非视距传播误差的室内三维三边定位算法,在此基础上设计和开发基于超宽带技术的机房室内定位系统,用于复杂机房环境的室内定位导航。实验证明,该定位系统比Wi-Fi、蓝牙指纹定位具有更高的定位精度,在复杂的机房环境下基于非线性最小二乘法进行目标函数求解的最优化方法与KNN算法相结合的室内定位方案具备较好的定位性能,为机房数据中心运维智能化的位置定位导航服务提供了有效的方法和手段。     

Design of Miniature UWB-Based Antenna by Employing a Tri-Sectional SIR Feeder

A novel ultra-wideband (UWB)-based microstrip antenna is presented in this work by using a slotted patch resonator, a tri-sectional stepped impedance resonator (SIR) feeder, as well as a reduced ground plane. The whole structure was realized on an FR4 substrate. The impact of incorporating several cases of ground planes on the input reflection has been thoroughly investigated under the same tri-sectional SIR feeder and by employing a slotted patch radiator. Since the complete ground plane presents an inadequate frequency response, by reducing the ground plane, the induced UWB responses are apparent while the antenna exhibits higher impedance bandwidth. The impact of both the uniform impedance resonator (UIR) as well as the SIR feeder on the input reflection has also been examined by following the same adopted reduced ground technique and using a slotted patch radiator. As a result, the UIR feeder exhibits a dual-band frequency response, when a wide notched band is incorporated in the range from 4.5–6.5 GHz. The dual-band response of the bi-sectional SIR feeder is still apparent with a narrower notched band in the frequency range from 4–5 GHz. As far as the tri-sectional SIR feeder is concerned, the UWB response is discernible without recording the existence of a notched band. Additionally, the antenna displays a higher impedance bandwidth compared with the previously reported steps. Our proposed antenna configuration is designed with highly compact dimensions and an overall size of 14 × 27.2 mm². Moreover, it operates under the impedance bandwidth of 2.86–10.31 GHz that can be leveraged for numerous applications where wireless systems are used. Our approach presents several advantages compared with the other reported UWB-based antennas in the literature, whereas the measured S₁₁ pattern is in good agreement with the simulated one.     

超宽带锥形电感特性研究

锥形螺旋电感是一种新型电感,在较宽的频带内有良好的一致性,在毫米波电路和光载无线通信系统（RoF Radio-over-Fiber）中有广泛的应用.本文对锥形螺旋电感感值、螺旋电感长度、直流电阻的计算方法进行了研究,给出了精确计算方法,其中,电感值误差在10.2%以内,直流电阻误差在6.5%以内;对锥形空心螺旋电感微波特性进行研究,提出了一种等效模型,该模型拟合计算结果与实测曲线有较好的一致性,使用该模型给出了螺旋电感宽带特性的详细理论推导,同时利用该模型首次对锥形螺旋电感的宽带特性进行了直观解释;最后,将绕制参数对电感微波性能的影响进行分析,引入单位长度电感量参数α和电感量-频率参数β,可对超宽带锥形电感微波特性进行优化,对某些特性进行快速优化.     

一种超宽带紧耦合相控阵天线设计

设计了一种阵列规模大小为8*8的超宽带紧耦合相控阵天线。首先,基于无限周期边界条件,采用等效电路模型理论分析方法,对阵列阵列单元进行了设计;其次,边缘截断采取了半无限周期阵列模型分析方法处理,降低了计算工作量并显著提升了阵列边缘截断处理优化效率;最后,根据改良后的半无限周期天线阵列模型,完成了8*8紧耦合阵列天线的设计。仿真结果表明,所设计天线可工作于3 ~ 17.5 GHz(5.7:1)频段,阵中多数单元于±45°的波束扫描范围内具有良好的匹配特性,天线辐射波束较好,阵面天线尺寸只有0.81λ_min*0.72λ_min*0.2λ_min。     

超宽带雷达频率开窗干扰抑制仿真分析

超宽带雷达因其信号频谱极宽,与调频无线电、移动通信等频段出现交叠,导致雷达接收通带内存在严重的射频干扰,影响雷达的性能。首先利用雷达方程分析了影响雷达探测覆盖能力的主要因素;然后分析雷达通带内干扰信号的特点并对其建模,之后在雷达回波信号处理环节引入陷波滤波机制实现对窄带干扰的开窗抑制;最后仿真分析了开窗抑制窄带干扰以及开窗个数对雷达探测能力的影响。仿真结果表明,对超宽带雷达进行频率开窗可有效抑制窄带干扰,但开窗个数过多时会造成雷达性能的下降,实验结果与理论分析相符。     

直扩超宽带系统中基于线性约束恒模算法的多用户检测

针对超宽带室内传输环境的慢时变特性以及超宽带信号的恒模调制方式,提出了一种基于线性约束恒模算法的盲自适应多用户检测方案。该方案首次将恒模算法引入直扩超宽带系统中的多用户检测,应用盲信号处理方法推导了恒模算法在线性约束条件下的全局最优性。理论分析及仿真结果表明,与基于训练序列的自适应多用户检测相比,该方案提高了有效的信息传输容量,同时在输出信干比及误码性能方面的损失不超过3dB,有效地做到了传输容量与误码性能之间的折衷,适用于室内超宽带的多用户高速接入场合。     

超宽带正交脉冲波形设计

超宽带系统利用窄脉冲传输信息,其系统性能受脉冲的功率利用率影响.为了使脉冲波形充分利用FCC功率谱密度规范所划分的频段,该文从最大化功率利用率的角度出发,采用半正定规划的方法设计了一组脉冲超宽带的正交波形.设计得到的脉冲波形具有时域持续时间短、频域满足FCC规范及功率利用率高等优点,并且不同脉冲间在零点处互相关系数小,正交性好.通过将目标函数中的2-范数转换成1-范数,可以进一步增加正交波形的功率利用率,从而有效提高接收端的信噪比.设计结果表明这种设计方法是一种满足规范要求的较为理想的方法.     

UWB信道盲估计的频域递归最小二乘实现

为了实现超宽带(UWB)信号高效、稳定接收,提出一种基于信道频域特性的UWB信道盲估计算法.利用跳时脉冲相位调制超宽带信号一维统计平稳特性,结合递归最小二乘算法计算,达到信道参数盲估计的目的.计算机仿真结果与最大似然法信道盲估计算法结果的对比表明,新算法在误码率为10-4时,信噪比增益约为3 dB.新算法可同时对多路信道进行估计,对幅度和相位不存在模糊因子,且具有低复杂度的优点.     

An optimized UWB correlator design with the consideration of the impacts from the ESD protection devices

Electrostatic discharge(ESD) failure has become an emerging challenge for radio frequency(RF) integrated circuits(ICs),which requires high ESD-protection for circuit applications in harsh environment.This paper discusses the design and optimization of an ultra-wideband(UWB) correlator circuit using ESDaware simulation design technique.Mixed-mode ESD simulation-design method and RF ESD characterization technique are presented for accurate ESD device design and ESD-induced parasitic effects extraction.The impact of ESD induced parasitic is carefully considered in the whole correlator design simulation by using a direct S-parameter insertion technique.The design is based on a commercial 0.18 μm RFCMOS technology.