基于模式理论的传输线高频串扰预测仿真

根据传输线理论建立均匀介质无损多导体数学模型,然后利用模式理论建立了不均匀介质无损多导体数学模型,并对多导体传输线间高频电磁串扰进行了仿真分析.为各类多导体传输线的设计和应用提供一定的参考.     

PCB上微带线间的串扰分析

用传输线理论知识对PCB板上平行走线之间的串扰作了分析推导,为PCB板上的布线设计提供了参考,证明了避免串扰的设计技术和原则。     

基于Hyperlynx的高速数据传输板SI研究

电子设计领域的快速发展,使得由集成电路构成的电子系统速度越来越高,PCB板的信号完整性问题已经成为高速电子系统设计能否成功的关键。本文介绍了信号完整性仿真的流程,并利用集成电路的IBIS等仿真模型以及Hyperlynx仿真工具等,对高速数据传输板的时钟和数据等关键信号进行了详细的信号完整性后仿真分析,验证了该高速数据传输板PCB布线设计的正确性。在工程应用中,该高速数据传输板运行稳定可靠,满足设计要求。     

一种微波介质谐振器介电常数测量方法

针对现有平行板开式腔谐振法测量介电常数时会有一部分能量顺着馈线和上下金属板之间的结构传输形成辐射损耗的特点,提出了一种复介电常数测量方法,通过在馈电侧上下金属板之间增加短路板来阻挡辐射损耗。设计制作了具有短路板的介质谐振器测试系统,采用单端口工作,给出了工作在TE011模下的介电常数和损耗角正切的计算方法,并对一圆柱形介质样品进行了测量试验。     

高速电路PCB板的反射问题分析及仿真

当今电子技术飞速发展,集成电路的频率不断提高,PCB板的密度也在逐渐增加,使得信号完整性问题越来越成为每一个电子工程师都必须要关注的问题.由传输线效应引起的反射问题就是其中非常重要的一个方面.分析了反射产生的原因,给出了抑制反射的方法,并结合实例进行了Protel仿真,通过仿真结果可以看到反射基本都得到了抑制.     

基于不均匀介质基底的传输线高频耦合干扰研究

对于多导体电磁耦合干扰问题,等效电路的方法简单实用,得到国内外研究学者的关注.利用传输线理论建立多导体传输线高频等效电路与数学模型,在前人研究的基础上,根据模式理论均匀无损传输线方程推导出不均匀无损传输线间高频耦合干扰的矩阵形式数学模型,并对导体传输线间的高频耦合干扰进行预测仿真分析.由此得出的结论,为各类多导体传输线抑制高频线间电磁干扰以及提高电气、电子设备和整个系统的工作可靠性提供了理论帮助.     

基于FPGA的高速高密度PCB设计中的信号完整性分析

根据摩尔定律,高速高密度印刷电路板(PCB)的设计变得越来越复杂。针对大型或特大型高速高密度PCB设计中信号完整性的一些关键问题,如：PCB层叠、传输线类型、特征阻抗计算、互连拓扑结构、端接技术、延迟匹配、串扰分析、差分布线等,通过理论分析、仿真验证、工程实践相结合的方式进行讨论,并给出相应的解决方法或设计规则。在此基础上,给出现场可编程门阵列(FPGA)多层PCB板设计原则。具体工程实验证明,在这些规则或机制的驱动下,高速高密度PCB的设计能够获得良好的实际效果。     

基于信号完整性的高速数据采集传输系统设计

高速PCB设计中必须面对信号完整性问题,并采取有效措施;基于信号完整性分析的高速PCB设计流程能够缩短产品开发周期,降低开发成本;根据这个流程设计了一个高速数据采集传输系统,仿真结果表明电路的信号完整性问题得到了改善,对数据采集系统的性能进行测试后表明AD的动态有效位数达到了10位;说明了在高速电路设计中采用基于信号完整性仿真设计是必要的,也是可行的。     

基于场路耦合的反激变换器板级辐射研究

辐射干扰问题是制约电源产品高频化、小型化的因素之一。基于场路耦合的仿真思路,建立MOSFET的电磁场有限元模型和高频变压器的等效高频电路模型。结合从SIwave电磁仿真软件中提取的PCB网络参数,对一款5 W输出的反激变换器的板级辐射干扰进行联合仿真,并对比了两种高频变压器模型对远场仿真结果的影响。实验结果表明,在230 MHz以内的频段3 m远场仿真超标频点与实测吻合,验证了该仿真方法的正确性,且简化的变压器二电容模型具有更宽频带的适用性;所得到的近场电磁场分布表明MOSFET和变压器副边的整流二极管是主要的辐射源。     

2.5GS/s高速DAC陶瓷封装协同设计

随着超大规模集成电路向着高密度、高频方向发展,保证高速信号的可靠传输成为封装电学设计中的关键。完成了一款转换速率为2.5 GS/s的14 bit DAC陶瓷外壳封装设计,利用芯片、封装和PCB的协同设计,保证了关键差分信号路径在2.5 GHz以内插入损耗始终大于-0.8 d B,满足了高速信号的传输要求;并结合系统为中心的协同设计和仿真,对从芯片bump到PCB的整个传输路径进行了仿真和优化,有效降低了信号的传输损耗和供电系统的电源地阻抗。     

基于Protel SDK的传输线分析与端接处理系统

印刷电路板走线传输线效应是影响印刷电路板走线信号质量的主要因素。本文结合ProtelSDK,提出一种采用Client/Server结构嵌入于Protel的计算机自动印刷电路板走线传输线分析及端接处理系统,该系统能对印刷电路板走线传输线分析,对存在问题的走线给出处理策略。     

千兆以太网交换机的信号完整性研究*

以千兆以太网交换机PCB设计出现的问题为背景,研究高速数字电路设计的信号完整性问题,从板层、电源和传输线三方面分析原因,并提出解决方法,测试表明取得了有效的结果。     

基于FPGA的无线接入点硬件平台的设计与实现*

基于认证、安全及QoS等方面的研究需要,提出了基于FPGA的HostAP设计方案,并搭建了无线接入点的硬件平台,在此平台上进行了硬件的裁减与集成;设计和实现了无线接入点的硬件电路,完成了无线接入点的高速PCB布局布线.在PCB布局布线的过程中,重点解决了高速印制电路板设计中的传输线效应问题,最后进行了实际的系统测试.     

基于AOI的PCB孔缺陷检测法

PCB(Printed Circuit Board,印制电路板)是提供电子零件安装与插接的基板,实现电子元器件之间的电气互连,是电子产品不可缺少的基本构成部分。过孔是PCB的重要组成部分,在PCB生产线上由于钻孔和电镀等工艺技术的限制,造成孔内缺陷,影响元器件的电气连接及焊接质量。因此为了保证过孔的可靠性必须进行缺陷检测。基于AOI(Automatic Optical Inspection,自动光学检测)原理,用计算机对PCB孔透光过程进行光学衍射建模仿真。将缺陷孔和无缺陷孔的仿真衍射图样进行比较,可判断出PCB孔是否存在缺陷。结果证明,这种缺陷检测方法具有可行性且操作简便。     

Line balancing of PCB assembly line using immune algorithms

Printed Circuit Boards (PCBs) are widely used in most electronic devices. Typically, a PCB design has a set of components that needs to be assembled. In a broad sense, this assembly task involves placing PCB components at designated location on a PCB board; fixing PCB components; and testing the PCB after assembly operation to ensure that it is in proper working order. The stringent requirements of having a higher component density on PCBs, a shorter assembly time, and a more reliable product prompt manufacturers to automate the process of PCB assembly. Frequently, a few placement machines may work together to form an assembly line. Thus, the application of more than one machine for component placement on a PCB presents a line-balancing problem, which is basically concerned with balancing the workload of all the machines in an assembly line. This paper describes the application of a new artificial intelligence technique known as the immune algorithm to PCB component placement as well as the line balancing of PCB assembly line. It also includes an overview of PCB assembly and an outline of the assembly line balancing problem. Two case studies are used to validate the IA engine developed in this work. The details of IA, the IA engine and the case studies are presented.     

薄片介质高速传动的动态仿真与分析

针对薄片介质在金融自动处理设备中传动和堆叠过程中常见的卡阻故障,采用RecurDyn计算薄片介质的力学特性,获得薄片介质的弹性模量与弯曲挠度之间的关系曲线,以用于确定不同新旧程度薄片介质的弹性模量;基于票券自动处理设备中的堆叠模块,对介质在传动过程中的变形和运动姿态进行仿真,计算支撑固件的不同长度所对应的介质弯曲挠度.结果表明：支撑固件长度越大,介质产生的弯曲挠度越大,有利于避免介质堆叠时发生卡阻问题.     

A case-based reasoning system for PCB defect prediction

The manufacturing process for a new Printed Circuit Board (PCB) design is often instable and might generate a number of defects during the complicated production process. Defects reduce the yield rate and increase the production costs. Although skilled engineers can predict the possible defect items for a new PCB product, this approach requires strong engineering experience and is time consuming. To conquer this problem, this research applies case-based reasoning (CBR) methodology to develop a defect prediction system for new PCB products. In the CBR system, each case is represented using the design specifications, defect items and corresponding costs. A vantage-based case indexing mechanism is developed to accelerate the case retrieval efficiency. In addition, a reasoning algorithm that considers the defect cost is proposed to infer the defect items that are interesting to PCB manufacturers. The system performance is analyzed to show the efficiency and accuracy of the proposed system. A practical implementation using a case-base provided by a PCB manufacturer is demonstrated.     

A wafer-level package of wideband microwave transmission system based on BCB/metal structure embedded in Si substrate

In this paper, a wafer-level package for a microwave transmission system has been implemented and tested. Three monolithic microwave integrated circuits packaged in one microwave system are first proposed. The packaged system consists of an up-converter, a drive amplifier and a power amplifier. All the modules are embedded in the cavities pre-etched in a low-resistivity silicon substrate. Benzocyclobutene layers are coated on the components and silicon substrate, serving as interlayer dielectrics. Gold bumps are used as electric interconnections between different layers. Gold micro-strip lines are employed as transmission lines. The electrical properties of the packaging structure are investigated. The design procedure is proposed and the simulation regarding transmission line has been done. The thermal property of the packaged system is simulated and detailed discussion is presented. The measured transmission characteristics of the packaged system shows that the modules can work at very wide band, at the range of 6–18 GHz (X/Ku band) and its gain agrees well with the theoretical results.     

Chaotic species based particle swarm optimization algorithms and its application in PCB components detection

An improved particle swarm optimizer using the notion of chaos and species is proposed for solving a template matching problem which is formulated as a multimodal optimization problem. Template matching is one of the image comparison techniques. This technique is widely applied to determine the existence, location and alignment of a component within a captured image in the printed circuit board (PCB) industry where 100% quality assurance is always required. In this research, an efficient auto detection method using a multiple templates matching technique for PCB components detection is described. The new approach using chaotic species based particle swarm optimization (SPSO) is applied to the multi-template matching (MTM) process. To test its performance, the proposed Chaotic SPSO based MTM algorithm is compared with other approaches by using real captured PCB images. The Chaotic SPSO based MTM method is proven to be superior to other methods in both efficiency and effectiveness.     

高温环境下测试信号传输的稳定性分析

针对测试过程中传输线受高温影响导致信号传输产生一定的不确定性的问题,提出了热电耦合的方法来研究导体的温度演变过程,计算温度变化影响下的电信号稳定性传输,并建立误差公式估算输入与输出电信号之间的关系。采用有限元方法建立了分析模型,讨论了外部环境与传输线的对流换热和通过电流时产生的焦耳热对导体产生的共同作用,以及影响电信号的稳定性传输的主要因素。此分析方法为提高高温环境下的结构测试的准确性提供了依据,对实际工程具有一定的指导意义。