900MHz微带封装宽边耦合巴伦的紧凑小型化研究

研究开发一种新型微带一体化封装宽边耦合巴伦,探讨平衡/不平衡型实际构成原理电路及巴伦奇偶模工作条件,由此运用ADS等仿真工具设计并优化出可适用于微带/多层宽边耦合小型紧凑化的封装巴伦,给出中心频率在900MHz微带/带状耦合型一体化封装宽带巴伦的仿真设计,实验电路与实测结果.     

一种小型共面波导UWB陷波天线的设计

随着无线通信技术的蓬勃发展,超宽带(Ultra-Wide Band)无线通信技术以其频带宽、低功耗等优点获得了高度重视,为了顺应这种发展趋势,本文介绍了一种小型共面波导UWB陷波天线,该天线工作频段覆盖2.2GHz-10.7GHz,在频段4.9GHz-5.9GHz具有陷波特性,实现了超宽带与WLAN的协同通信。     

V波段CMOS注入锁相二分频器设计

基于IBM 90 nm RF CMOS工艺,设计了49.8～55.8 GHz锁相范围的毫米波注入锁相分频器.对电感、共面波导和微带线进行对比.将Q值较高的电感用于振荡器部分以得到较好的相位噪声,将共面波导用于输入匹配部分以得到较宽的输入匹配,注入节点处感性元件采用共面波导以减小版图面积.对振荡器和输入晶体管的偏置电压进行优化,得到较高的注入效率以提高锁相范围.     

一种宽波束矩形单极天线的设计

设计加工了一种具有宽波束特性的矩形单极天线。该天线为矩形平面单极天线,通过共面波导方式进行馈电。利用HFSS对平面天线仿真优化,对天线的阻抗特性和辐射特性进行分析,仿真结果表明,天线在宽频带内实现低仰角,方位面能偶全向扫描,阻抗带宽7.3~12.6GHz,最大增益可达4.1d B,辐射稳定性好,可用于机载天线的共形单元。     

一种超宽带低噪声放大器的仿真设计

本文介绍了一种超宽带低噪声放大器的仿真设计,采用负反馈技术提高了工作带宽并增强了放大器的稳定性。通过ADS软件的仿真优化提高了设计效率,并进行了原理图-版图协同仿真验证。实验测试该超宽带低噪声放大器在0.1GHz～1.5GHz的带宽内增益大于30dB,增益起伏小于±1.8dB,噪声系数小于1dB,P1dB大于15dBm。     

X波段四路功率合成器

文章介绍了一种基于波导-鳍线-微带线过渡的4路功率合成器结构,并通过Ansoft HFSS电磁仿真软件对其进行了仿真分析和优化设计。在整个X波段(8GHz～12GHz)内,功率合成器的插入损耗小于0.25d B,回波损耗大于-15d B,且通过加载微带扇形结构使同一平面上端口的隔离度大于8.5d B。结果表明,此结构在实现微波功率合成方面具有一定的应用前景。     

一种平面结构的宽带水平极化全向天线

设计并加工了一种平面结构的宽带水平极化全向天线,该天线由四个改进的弯曲偶极子加上各自的耦合单元构成。天线在水平面内能很好地实现全向辐射特性,在4.8～6.8GHz的频带范围内,回波损耗小于-10dB,水平极化不圆度小于±0.7dB,交叉极化优于-20dB。     

一款共面电容耦合探针馈电印刷天线的设计

本文介绍了一款新型的宽带微带贴片天线.该天线结合探针馈电和共面电容耦合原理,将天线的带宽进行了有效的拓展.本文在仿真优化该天线的基础上,制作了一款以FR4为介质的基于共面电容耦合的印刷天线,结果表明：该天线具有良好的宽频带特性.     

超宽带无线通信中同步技术的研究

简述了超宽带技术的特点,对当前超宽带技术中的几种同步技术的主要思想进行综述、并分析近几年来几种经典算法各自的优缺点以及改进的方向。最后对超宽带同步技术中进一步需要解决和研究的问题进行了讨论。     

一种大功率高方向性定向耦合器研制

<正>定向耦合器是微波传输系统中常用的一种微波无源器件,可以用于信号的分离与隔离,也可以从微波传输路径中耦合一部分能量用于监测微波功率。通过传输介质划分,常用的定向耦合器分为带状线为主体的带状线耦合器和波导为主体的波导耦合器,其中带状线定向耦合器体积小、方向性高,是目前广泛使用的一种,但是由于其功率容量较低,在大功率微波链路中很少使用。传统波导耦合器由两路波导组成,体积大、成本高,使用时需要接入波导同轴转换,操作复杂而且容易引入额外误差。本文设计的定向耦合器结合了带状线的小体积与波导定向耦合器的大功率特点,产品结构如图1所示。     

一种小型超宽带平面和差网络

提出了一种新型宽带功分器,并利用该功分器设计出了超宽带的和差网络。此网络以功分器以及反相巴仑作为基本单元,将2器件通过空气桥背接得到等效的180o耦合器,4个这样的180o耦合器拓扑组合实现了超宽带的和差网络。实验结果表明,该网络性能优良,具有结构紧凑、加工方便和成本低的优点。     

Characterization of a microflow cytometer with an integrated three-dimensional optofluidic lens system

Flow cytometry is a standard analytical method in cell biology and clinical diagnostics and is widely distributed for the experimental investigation of microparticle characteristics. In this work, the design, realization, and measurement results of a novel planar optofluidic flow cytometric device with an integrated three-dimensional (3D) adjustable optofluidic lens system for forward-scattering∕extinction-based biochemical analysis fabricated by silicon micromachining are presented. To our knowledge, this is the first planar cytometric system with the ability to focus light three-dimensionally on cells∕particles by the application of fluidic lenses. The single layer microfluidic platform enables versatile 3D hydrodynamic sample focusing to an arbitrary position in the channel and incorporates integrated fiber grooves for the insertion of glass fibers. To confirm the fluid dynamics and raytracing simulations and to characterize the sensor, different cell lines and sets of microparticles were investigated by detecting the extinction (axial light loss) signal, demonstrating the high sensitivity and sample discrimination capability of this analysis system. The unique features of this planar microdevice enable new biotechnological analysis techniques due to the highly increased sensitivity.     

Characterization of wall dispersive and attenuative effects on UWB radar signals

This paper addresses the potentials of ultra-wideband (UWB) through-wall imaging radars compared with conventional narrowband systems. The challenges that limit the utilization of high precision UWB systems are examined with the aim of mitigating them. These challenges include multi-path, pulse dispersion, and antenna effects on the pulse shape due to angles of transmission and arrival. The propagation of UWB signals through walls is a crucial factor in determining the success of UWB radar technology. UWB signals, when propagating through walls, not only suffer attenuation but also distortion due to dispersive properties of the walls. This paper examines time- and frequency-domain techniques for measuring the electromagnetic properties of construction materials in the UWB frequency range. The measured parameters provide valuable insights in appreciating the capabilities and limitations of the UWB technology. Special attention is paid to time gating as a mean to extract the direct-path signal from the multi-path components. Both single-pass and multi-pass models are discussed. Multi-pass models account for the multiple reflections within the wall while the single-pass model assumes the possibility of gating out a single transmission. The partition-dependent narrowband propagation model is modified to account for the ultra-wide bandwidth of the signal. The paper illustrates the application of the modified model in indoor environments. The modified model is helpful in estimating the link power budget. It is also useful in studying the performance of UWB systems for indoor communication and positioning applications.     

基于消谐波技术的正交双相逆变电源的设计

采用基于消谐波技术通过直接数字合成正弦调制波(SPWM)和余弦调制波(CPWM)的正交双相信号,由单片机控制器控制波形存储器EPROM产生SPWM和CPWM,经过驱动电路控制逆变器,设计成正交双相逆变电源。电路结构简单,运行稳定可靠,输出电压波形无失真,可广泛应用于航空、航海、电力、铁路、邮电、医疗等诸多领域。     

Adaptive robust control for planar n-link underactuated manipulator based on radial basis function neural network and online iterative correction method

This paper presents an adaptive robust control strategy based on a radial basis function neural network (RBFNN) and an online iterative correction method (OICM) for a planar n-link underactuated manipulator with a passive first joint to realize its position control objective. An uncertain model of the planar n-link underactuated manipulator is built, which contains the parameter perturbation and the external disturbance. The adaptive robust controllers based on the RBFNN are designed to realize the model reduction, which makes the system reduce to a planar virtual three-link underactuated manipulator (PVTUM) and simplifies the complexity of the system control. An online differential evolution (DE) algorithm is used to calculate the target angles of the PVTUM based on the nominal model parameters. The control of the PVTUM is divided into two stages, and the adaptive robust controllers are still employed to realize the control objective of each stage. Then, the OICM is used to correct the deviations of all link angles of the PVTUM caused by the parameter perturbation, which makes the end-point of the system gradually approach to its target position. Finally, simulation results of a planar four-link underactuated manipulator demonstrate the effectiveness of the proposed adaptive robust control strategy.     

中国专利活动投入要素的产出弹性分析——基于状态空间模型的变参数估计

 专利产出水平体现了一国的科技创新能力,对国家经济发展的贡献份额越来越大,在追求最优的专利投入产出效益过程中,对专利投入产出的定量分析必不可少。与以往文献注重静态分析不同,本文首次分析了专利活动的投入与产出之间的动态关系。本文在知识生产函数理论的基础上构建了专利生产函数模型,在多变量分析框架下,将其设定成基于状态空间形式的变参数模型,根据Kalman滤波法,运用一组时间序列数据对参数进行连续地估计,并对其波动进行了分析。     

An efficient micromixer based on multidirectional vortices due to baffles and channel curvature

An efficient planar micromixer based on multidirectional vortices in a curved channel with radial baffles is proposed and examined in this work. The curvature of the microchannel and the radial baffles induce vortices in different directions. The multidirectional vortices and the converging-diverging flow caused by the baffles contribute together to the enhancement of mixing. The micromixer is fabricated with polydimethylsiloxane by a single planar microlithography process and the mixing behaviors are observed by a confocal spectral microscope imaging system to validate the simulation obtained by a commercial code. The simulation and experimental results are in reasonable agreement. The concentration distributions and flow patterns obtained reveal the following trends. (i) The mixing efficiency of the basic C-shaped micromixer with the first baffle attached to the internal cylinder and the second attached to the external cylinder is better than that of the C-shaped micromixer with inverted arrangement of baffles. (ii) When the radius of the curved channel and the width of the passage between the baffle and the cylindrical wall are small enough and the Reynolds number (Re) is large enough, an extra separation vortex develops in the downstream of the second baffle. This phenomenon is one of the reasons of trend (i). (iii) A micromixer consisting of a few basic C-shaped micromixers connected by straight channels may generate a high degree of mixing for the case with a large Re.     

Input–output finite-time stabilization for MJSs with time-varying delay: An observer-based approach

This paper deals with the input–output finite-time stabilization problem for Markovian jump systems (MJSs) with incompletely known transition rates. An observer-based output feedback controller is constructed to study the input–output finite-time stability (IO-FTS) problem. By using the mode-dependent Lyapunov–krasovskii functional method, a sufficient criterion checking the IO-FTS problem is provided. Then, an observer and a corresponding state feedback controller for the individual subsystem are respectively designed to solve the input–output finite-time stabilization problem for the systems. Finally, a numerical example on the mass-spring system model is investigated to bring out the advantages of the control scheme proposed in this paper.     

Event-based discrete-time multi-agent consensus over signed digraphs with communication delays

The ability to ensure the desired performance of the cooperative-antagonistic multi-agent networks (MANs) in the presence of communication constraints is an important task in many applications of real systems. In this paper, under the proposed event-triggered condition (ETC), different types of consensus are obtained under different network topology. We concentrates on the event-based bipartite consensus. It is shown that under the proposed ETC (i) the addressed cooperative-antagonistic network with arbitrary communication delays reaches bipartite consensus provided that the network is balanced; (ii) the network model reaches zero if the network is unbalanced. Further, to avoid the continuously verifying the triggering condition, a self-triggered algorithm is proposed for realizing the bipartite consensus of the network model. A numerical example is given to illustrate the effectiveness of the theoretical results.