Optimal Lossy Matching by Pareto Fronts

Although lossy matching is not a standard antenna matching technique, well-designed losses can facilitate wide-band matching of otherwise unmatchable antennas. The lossy matching designs developed in this paper are based on the Pareto front. These Pareto front computations permit the circuit designer to graphically select optimal gain-reflection tradeoffs for lossy matching, readily incorporate other lossless matching bounds, and provide a general approach to difficult wide-band matching problems.     

An Optimal Stability Matching Algorithm for DAG Blockchain Based on Matching Theory

IOTA is a typical blockchain designed for IoT applications. The Markov chain monte carlo algorithm (MCMC) used in IOTA may lead to a large number of unverified blocks, which increases transaction delay to a certain extent. We propose a Stable matching algorithm (SMA) based on matching theory to stimulate nodes to verify blocks, thereby reducing the number of unverified blocks and the consensus delay. The structure of our IoT blockchain uses the Directed acyc1ic graph (DAG) to improve the transaction processing capability. The nodes in the network are abstracted as transaction issuers and transaction verifiers. A verification service scheduling system is used to assign transactions to the verifiers and achieve the optimal matching. We designed a trust evaluation mechanism which offers verifiers references and awards to check transactions. The simulation results show that SMA can significantly reduce the number of orphan blocks and improve the transaction throughput, which helps to improve the reliability of the IoT blockchain.     

多端互连线网络布线时延的研究

互连线时延是集成电路设计中非常重要的影响因素。本文根据Elmore延迟模型推导出多端互连线的延迟估算公式，得出了在满足设计规则的前提下，多端互连线网络应尽量遵守的布线规则，即互连线之间不要有重叠，且从源点到每个终点都要走最短的曼哈顿路径。这种布线规则可以在不增加芯片面积的基础上使互连线时延减少，这对指导高速IC芯片的版图设计有重要的理论和实践指导意义。     

一种多端口器件测量技术

给出了一种用二端口矢量网络分析仪(VNA)对多端口器件进行测量的方法,该方法运用简单的迭代法,减小由于其余端口所接负载的非匹配性引入的误差,易于通过软件实现。利用该方法对三端口器件巴伦进行测量,并将最后结果与三端口VNA测得的结果进行比较。比较结果表明,幅度误差小于0.2dB,相位误差小于3°。该方法在多端口VNA不可获得的情况下,可以应用到多端口器件的精确测量上。     

基于自适应最优聚类的目标匹配跟踪算法

提出了一种基于新的自适应最优聚类的模板匹配跟踪方法。利用模式分类准则计算最优聚类数,然后根据最优聚类数采用k-均值方法进行多次聚类。根据聚类结果计算熵矢量和距离矢量,组合得到特征矢量,利用特征矢量进行匹配跟踪。匹配采用简单的相似性准则,实时模板更新算法为多模更新。测试结果表明,该算法针对不同的目标能自适应地选择聚类参数,在目标发生几何变化时,能实现精确稳定的跟踪。     

基于自适应最优聚类的目标匹配跟踪算法

提出了一种基于新的自适应最优聚类的模板匹配跟踪方法。利用模式分类准则计算最优聚类数, 然后根据最优聚类数采用k-均值方法进行多次聚类。根据聚类结果计算熵矢量和距离矢量, 组合得到特征矢量, 利用特征矢量进行匹配跟踪。匹配采用简单的相似性准则, 实时模板更新算法为多模更新。测试结果表明, 该算法针对不同的目标能自适应地选择聚类参数, 在目标发生几何变化时, 能实现精确稳定的跟踪。     

基于空间关系的子区域最佳匹配算法

该文提出了一种基于空间关系的图像检索算法子区域最佳匹配法。这种算法首先根据符号投影模型,将图像内目标抽象为带有多个属性的图标。然后,利用搜索邻节点的等角度区域最近原则、划分子区域的中心点法、图论中的广度优先算法进行图标匹配。最后,根据所定义的局部区域相似距离及图间距离来计算图像与图像之间的相似度,进而完成基于图像内部空间关系的检索。该文以这种算法为核心,构建了一个篮球站位分析演示系统,并用实际数据验证了所提出的基于空间关系的图像检索方法的有效性。     

多端口功率分配器S参数的计算机分析

本文给出复杂网络任意端口连接理论，从而可以方便地进行多端口功率分配器的Ｓ参数计算机分析，理论计算与实测结果作了比较，这一理论也适用于其它多端微波元件的分析。     

基于遗传算法的宽带匹配网络的优化设计

本文采用遗传算法优化设计宽带匹配网络,通过适当的编码可同时对网络的拓扑结构和元件参数进行优化,并给出设计实例,通过与实频法相比较,表明遗传算法设计的匹配网络具有更优的匹配性能,说明遗传算法是一种设计匹配网络的有效方法。     

Design of Crystal-Type Multiport Optical Quasi-Circulator

An alternative macrooptic design of crystal-type multiport optical quasi-circulator is proposed. A prototype of six-port optical quasi-circulator was fabricated and tested with insertion loss of 1.97 dB, and isolation of 39.6 dB. The advantages of this design include high performance, being polarization-independent , and resolved polarization-mode dispersion. In addition, the number of ports can be easily expanded.      

变形金刚

高中生山姆终于拥有了自己平生第一辆汽车,这车外观虽然破旧点,但是却仿佛通人性一般保卫着他和女友。有一天,这辆黄色的二手车突然变形成为了一个高大的机器人。原来,来自外星球的可变形机器人已经追踪着     

天线宽带匹配网络的粒子群优化设计

提出了基于粒子群优化算法(Particle Swarm Optimization,PSO)设计天线宽带匹配网络的方法;采用了等效阻抗方法解决了UHF频段天线宽带匹配网络实际制作中元件值随频率畸变较大的困难;最后利用上述方法设计了一付30~512MHz全向超宽频带小型化天线的匹配网络,设计结果使得带内VSWR<3.0,并与实验结果吻合良好。     

3G基站射频前端LNA阻抗匹配优化设计

针对1．9GHz的3G基站射频前端LNA电路中的阻抗匹配问题,把厂家提供的小信号S参数制成S2P文件,然后将其导入EDA软件中搭建LNA电路的输入、输出端口匹配电路,并结合噪声系数和最大增益进行了阻抗匹配优化设计,并对优化后的LNA电路进行了仿真分析．仿真结果表明：在LNA电路的增益得到提高的同时,反射系数得到了显著的改善,达到了阻抗匹配优化设计的目的．该设计方法是解决3G基站射频前端LNA阻抗匹配问题的有效途径之一．     

Multiport power divider-combiner circuits usingcircular-sector-shaped planar components

A sector-shaped configuration for designing planar power divider-combiner circuits that are compatible with microstrip circuits is discussed. This configuration is analyzed using the two-dimensional planar circuit approach. Expressions for impedance matrix parameters of multiport sectorial planar circuits are given. Theoretical and experimental results reported for 90° and 180° power dividers are in good agreement     

Thermal Noise from a Passive Linear Multiport

The thermal noise from passive multiports is discussed from fundamentals so that it can be understood, measured, or calculated by a microwave engineer. The multiports are assumed to have a uniform temperature, but with no restriction on reciprocity or mismatch. The noise temperature, T/sub N/, contributed by such a multiport is T/sub N/=A T where T is its physical temperature and A is its absorption coefficient. An approximate method of measuring A, and a method of measuring an A as small as 0.008 within 5 percent, are pointed out. Also, exact and approximate expressions for A in terms of scattering matrix elements and termination reflection coefficients are derived. Finally, the crosscorrelation of the noise from different ports is briefly considered.     

Planar Multiport Quadrature-Like Power Dividers/Combiners

A new class of planar, multiport power dividers/combiners is presented that is a generalization of the branch-line four-port 3-dB quadrature hybrid. They are suitable for combining an arbitrary number of identical reflection-type or transmission-type devices while maintaining a match at the input port. Experimental results are included for a four-way hybrid power divider/combiner.     

基于磁性光子晶体的多端口环行器设计

基于二维三角晶格和正方晶格光子晶体分别设计了六端口和八端口光子晶体环行器.环行器由硅介质柱光子晶体波导和铁氧体介质柱缺陷构成.所设计的六端口环行器每个波导连接处只有一个铁氧体材料,能够有效降低损耗;八端口环行器波导连接处添加了多个铁氧体材料可有效提高隔离度.使用有限元法对电磁波在环行器中的传输进行了仿真验证.计算结果表明,六端口环行器各端口的隔离度达到22～38 dB;八端口环行器各端口的隔离度达到21.7～40.5 dB.设计的多端口环行器具有结构简单紧凑、隔离度高、损耗低的优点.     

New March Tests for Multiport RAM Devices

This paper describes three new march tests for multiport memories. A read (or write) port in such a memory consists of an n-bit address register, an n-to-2ⁿ-bit decoder (with column multiplexers for the column addresses) and drivers, and a K-bit data register. This approach gives comprehensive fault coverage for both array and multiport decoder coupling faults. It lends itself to a useful BIST implementation with a modest area overhead that tests these faults and achieves low test application time.     

Transmission-Line Transformers

The radio-frequency transformers described in this paper consist of matched transmission lines of equal length and characteristic impedance. The lines are connected according to rules given in the text. These transformers exhibit a very broad frequency response which can be readily estimated; two methods of analysis are presented. The computations agree well with the test results.