微带贴片天线与印刷四臂螺旋天线的组合应用

采用微带贴片天线与印刷四臂螺旋天线相组合的方式,完成铱星通信和北斗定位通信的功能,通过特殊机械结构的设计,实现二者电气性能的互补优化。     

一种用于移动接收地面数字电视的天线设计

本文介绍了近几年兴起的地面数字电视系统的结构 ,并着重叙述了移动中接收地面数字电视的全方位圆柱体微带螺旋天线的设计     

宽带微带贴片天线的研究进展

文章论述了微带贴片天线频带展宽方面的研究进展,主要介绍了几种新型的大带宽微带贴片天线。这些天线采用了在贴片或接地板“开窗”,附加负载,增加片元等方法来改进微带贴片天线的窄频特性,同时使其向小型化,结构简单化方向发展,使微带贴片天线的应用范围得到进一步的扩大。     

磁性基片双频三角形微带贴片天线

采用国内首创的新型有机磁性材料做基片，提出一种创新设计实现了微带贴片天线的双频工作。这是通过在三角形微带贴片的底边加载矩形凹槽来实现的，结构简单且双频比易于调节。由于采用了新型磁性基片，使天线尺寸比相同频率的常规贴片天线缩小，而具有比常规微带天线宽得多的带宽。文中给出了仿真和实测结果，证明了设计的有效性．     

微带贴片天线的分析方法

文章首先简要介绍了微带贴片天线的馈电方式,然后给出了微带贴片天线的三种常用数值分析方法,并用基于上述分析方法的两种仿真软件对一种倒F天线进行了仿真,从仿真的S11参数和方向图可知,天线具有较好的性能,这两种仿真软件的结果是基本相同的。     

电调微带贴片天线CAD

研究了探讨针馈电变容管加载的微带贴片天线的电特性,结果表明,在以未加载微带贴片天线的谐振频率2．2GHz为中心,可获得50％的有效阻抗带宽,我们用最简单的传输线模型估算谐振频率,实难结果与预测相当符合。     

基于Sierpinski微带分形贴片天线的特性分析

该文分析了一种新型的微带贴片天线——Sierpinski三角形垫片,并利用Ensemble7.0天线仿真软件对此天线进行了仿真设计。基于Sierpinski三角形垫片的微带分形贴片天线具有多频带特性,可广泛地应用于无线、卫星和移动通信中。     

用于天线RCS减缩的分形微带贴片天线

本文给出一种分形微带天线在天线雷达散射截面(RCS)减缩中应用的示例.分形结构具有独特的空间填充性能,利用该性能可以探索分形天线在天线RCS减缩中的应用.设计出的分形天线与常规天线的辐射性能进行了比较,可以看出分形天线基本保持了原辐射性能.同时比较了两者的散射性能,可以看出分形天线有一定的RCS减缩效果.本文的内容对天线隐身有一定的借鉴作用.     

双层微带贴片天线单元的实验研究

针对微带贴片天线频带较窄的缺点，提出了一种能使频带显著增宽的双层微带贴片天线的新结构，对之进行了宽频带匹配的实验研究。适当地调整上、下两层贴片的位置，并在下贴片的四周加上无源导体条带，得到ＶＳＷＲ≤２时（相对频宽达３０％左右）和ＶＳＷＲ≤１．３时（相对频宽达１８％左右）的良好结果。     

用于多频通信的微带分形贴片天线

本文分析了一种新型的方形微带分形贴片天线,天线为Sierpinski毯的形式,可工作于三个频段。对此天线采用基于有限元法的软件作了理论分析,并做出实物进行了实验测量。此天线在无线、卫星和移动通信应用中很有前途。     

Fundamental superstrate (cover) effects on printed circuit antennas

The fundamental effects of superstrate (cover) materials on printed circuits antennas are investigated. Substrate-superstrate resonance conditions are established which maximize antenna gain, radiation resistance, and radiation efficiency. Criteria are determined for material properties and dimensions for which surface waves are eliminated and a radiation efficiency due to substrate-superstrate effects ofe_{s} = 100percent is obtained. Criteria for nearly omnidirectionalbar{H}-plane patterns and nearly omnidirctionalbar{E}-plane patterns are presented. Finally, a general criterion is given for choosing a superstrate to optimize efficiency for the important case of nonmagnetic layers with the antenna at the interface.     

Design method and material technologies for passives in printed circuit Board Embedded circuits

The integration of passive components into the printed circuit board (PCB) as embedded passives integrated circuits (emPIC) results in a higher power density of power converters. To achieve a highly automated, low cost, integral manufacturing, the devices are constructed layer wise. Materials and processes necessary for the manufacturing of such circuits are described in this publication. Especially for magnetic components like inductors and transformers the design of such thin components is challenge. Because of the high aspect ratio, traditionally used models lead to a high calculation effort or use nonappropriate approximations. This contribution presents an analytic approach for the design. The model considers the magnetic flux distribution in the core and in the winding area and therefore allows a precise calculation of the inductivity as well as the losses in the device and their distribution. It is very well suited for a parametric analysis and thus for the synthesis of thin planar magnetic components. Material technologies for the construction of the capacitive layers and the magnetic cores are investigated. A ferrite polymer compound is adapted to be compatible with the PCB laminating process. Accordingly a 60-W offline converter was designed and fabricated using the new technology. Its transformer is entirely integrated in the PCB as well as 11 capacitors. Standard PCB lamination processes are used for the layerwise integration of the components. The circuit needs an area of the size of a credit card with a PCB thickness of 4 mm. Up to 82% efficiency could be demonstrated.     

PCB磷铜阳极材料的应用及发展趋势

介绍了PCB制造中磷铜阳极在酸性镀铜中的应用;及微晶磷铜阳极材料在高品位PCB制造中的优点和发展趋势。     

Effect of surface finish material on printed circuit board for electrochemical migration

This study investigates whether the electrochemical migration (ECM) is affected by factors such as the printed circuit board (PCB) surface finish, distance between the electrodes and bias voltage under water drop (WD) and polarization tests. The main element of the dendrite structure for ENIG (electroless nickel and immersion gold), electroless Ag and electroplate Sn was nickel, silver and tin, respectively. The order of speed in which the dendrite structure was formed from the cathode electrode to the anode electrode on the PCB with various surface finishes was electroless Ag, electroplate Sn and ENIG, irrespective of the distance between the electrodes and the bias voltage. The ECM rate was increased by decreasing the distance between conductors of the opposite polarity and increasing the bias voltage. The order of corrosion rate in distilled water with pH 6.5 and NaCl 1.0 wt% solution was electroless Ag, electroplate Sn and ENIG. This trend was corresponded with the tendency for ECM rate.     

厚铜PCB用高填充性半固化片的研制

一般地,106半固化片的树脂含量（简称RC）只能达到75％左右。因厚铜（铜厚达到105μm及以上）印制电路板的线路间需要更多的树脂来填充,故普通工艺制造的半固化片就很难满足厚铜印制线路板的填胶性。因此,本文研究了提高半固化片RC的新工艺方法,从而改善半固化片对厚铜印制线路板的填胶性能。     

高频高速印制板材料导热性能的研究进展

随着电子技术的发展,对高频高速印制板导热性越来越高的要求。除了开发高成本的高导热性聚合物材料外,在聚合物中填充高导热性的无机材料也是提高高频高速印制板基材导热性能的有效方法,而且填充型复合材料可以用理论模型预测其导热系数。主要综述了填料的形貌、分布与表面改性对填充型复合材料导热系数的影响等方面的研究进展。     

屏蔽挠性印制电路（FPC）

概述了高频电路或者传送电路中电磁屏蔽材料和方法的开发和设计,可以维持FPC最大特征的柔软性,提供优良的电磁屏蔽效果。     

Electromagnetic interference (EMI) reduction from printed circuit boards (PCB) using electromagnetic bandgap structures

As digital circuits become faster and more powerful, direct radiation from the power bus of their printed circuit boards (PCB) becomes a major concern for electromagnetic compatibility engineers. In such multilayer PCBs, the power and ground planes act as radiating microstrip patch antennas, where radiation is caused by fringing electric fields at board edges. In this paper, we introduce an effective method for suppressing PCB radiation from their power bus over an ultrawide range of frequencies by using metallo-dielectric electromagnetic band-gap structures. More specifically, this study focuses on the suppression of radiation from parallel-plate bus structures in high-speed PCBs caused by switching noise, such as simultaneous switching noise, also known as Delta-I noise or ground bounce. This noise consists of unwanted voltage fluctuations on the power bus of a PCB due to resonance of the parallel-plate waveguiding system created by the power bus planes. The techniques introduced here are not limited to the suppression of switching noise and can be extended to any wave propagation between the plates of the power bus. Laboratory PCB prototypes were fabricated and tested revealing appreciable suppression of radiated noise over specific frequency bands of interest, thus, testifying to the effectiveness of this concept.     

印制电路厚铜板制作的几种特殊方法

随着印制线路板产品的发展,好些电源类线路板面铜厚度已超出172 m或更高,对于大于172 m以上的厚铜板在制作过程中难度也越来越大。介绍了几种主要困扰厚铜板制作的特殊方法,来减少生产过程中的钻孔毛刺,蚀刻毛边,阻焊油墨气泡等厚铜板常有的几种问题,希望能给同行提供一些参考!     

Coreless printed circuit board (PCB) transformers for powerMOSFET/IGBT gate drive circuits

Gate drive circuits for modern power electronic switches, such as MOSFET and insulated gate bipolar transistor (IGBT), often require electrical isolation. This paper describes the modeling and experimental results of some coreless printed circuit board (PCB)-based transformers that can be used for MOSFET and IGBT devices at high-frequency (500 kHz to 2 MHz) operation. PCB-based transformers do not require the manual winding procedure and thus simplify the manufacturing process of transformer-isolated gate drive circuits. With no core loss, coreless transformers are found to have favorable characteristics at high-frequency operations. This project demonstrates an important point that the size of the magnetic core can approach zero and become zero when the frequency is sufficiently high