基于高Q谐振腔法的微波复介电常数的测量

随着微波电路在工作时的频率的提高，体积逐渐减小，对于适用在微波电路中薄片状介质的需求增加了，而复介电常数是介质基片的一个主要参数。本文对就微波介质复介电常数测量的高Q谐振腔法进行了简单的介绍。     

高速嵌入式系统中电源噪声抑制方法

根据平面腔体谐振模型理论推导出高速嵌入式电路电源平面对阻抗函数关系式,分 析了电源平面对的谐振特性与PCB板材、介质层厚度以及导体平面的电导率之间的关系,得 出可通过减小介质层厚度、使用高介电常数的介质材料以及增加介质损耗等3种方法来抑制 电源平面对的谐振效应,并使用全波仿真方法验证了可行性。从时域仿真了高速电路中的噪 声传播与电源平面谐振的相互关系,结果表明,通过抑制电源平面对谐振阻抗可将电源噪声 减 小至原有结构的15%,从而有效提高系统的电源完整性。     

抛物方程法在森林环境电波传播特性预测中的应用

为提高大区域森林环境电波传播特性预测的准确性,研究抛物方程（PE）法在森林环境电波传播特性预测中的应用,提出了基于抛物方程的森林模型。该模型采用PE法实现准确快速求解,考虑森林在垂直方向上的非均匀性,引入森林分层模型,将森林分为树冠、树干两个均匀有耗介质层,并根据森林区域的特性参数确定各有耗介质层的等效介电常数,相比于传统将森林等效为一个给定介电常数的均匀有耗介质层,能够更准确地描述森林对电波传播的影响。将其应用于三种常见绿叶林的电波传播特性预测中,仿真结果表明,该模型能够反映不同区域、不同植被种类的森林对电波传播的影响差异,有效预测大区域森林环境电波传播特性。     

短波海面反射损耗模型研究

短波在信号传输中具有重要的应用,在海面的反射会引起损耗,为计算传输过程的损耗。基于一般介质的反射损耗模型,具体应用到以海面为电波为反射介质,得到适用于海面反射损耗的模型。结合短波传输过程中在空气以及电离层的损耗模型,设定条件并计算传输总损耗以及在满足信噪比条件下的跳跃数。结果表明,发射仰角以及发射频率的不同会造成电波传输损耗以及跳数有较大差异,合理设定参数能够减小损耗。     

谱激电法柯尔-柯尔模型频谱参数特性研究

谱激电法也叫SIP,是一种激发极化的分支方法。SIP以地下介质复电阻率的频谱特性为依据,通过相应的频谱参数来对电性异常体进行评价。本文简单描述了Cole-Cole复电阻率等效模型。选取了不同的频谱参数值对频谱参数特性做了分析。     

铁氧体厚度对Ka频段微带结环行器特性的影响

研究了铁氧体厚度对微带结环行器传输特性的影响,结果表明,随着铁氧体厚度降低,环行器的性能逐渐降低.当用介质来替代部分铁氧体时,介质材料的介电常数越小,越容易获得较好的环行性能,这为设计小型化的铁氧体环行器提供了有价值的参考.     

微波LTCC内埋置电感设计与参数提取

采用单π拓扑结构建立LTCC内埋置电感等效电路模型,并利用此模型来提取有效参数及各种寄生参数;采用相对介电常数为7.8、介质损耗为0.0015的微波陶瓷材料,以及银作为内电极,设计出400 MHz频率下大小为6.6 nH的LTCC内埋置螺旋电感,自谐振频率达2.2 GHz,最大Q值为50.2.     

技术转让与合作

高导热AlN陶瓷基板 氮化铝(AlN)陶瓷具有热导率高,热膨胀系数与Si相当,介电常数、介质损耗小,绝缘,无毒等优异性能,作为新一代电子化工用散热基板材料,用于大规模、超大规模集成电路基板和封装,大功率分立器件基板、多片模块电路散热器、功率厚膜电路、固态继电器、功率晶体管和开关电源基板等,在微电子、高科技领域中有广阔的应用发展前景,是我国电子工业“八五”、“九五”重点开发项目。南京化工大学经多年研     

机车异步牵引电动机DTC控制系统优化

针对DTC控制在低速运行时的磁链脉动大等不足，在电压空间矢量控制理论基础上，从异步电机损耗模型出发，以磁链、转速为基本未知量，研究了他们与各种损耗之间的关系，使磁链达到最优，提高DTC控制性能，减小电动机相应损耗。     

平行耦合微带线的一种简易算法

本文介绍一种计算精度足够高的平行耦合微带线的简易算法。此算法是借助于保角变换,把平行耦合微带线变换成“单一”微带线,从而利用单线公式作中间计算步骤而推演出来的一种算法。按此法,采用具有通用函数功能的袖珍计算器,即可对任意介电常数的介质基片材料进行电路特性分析或综合设计。文中给出了主要计算公式、分析算法和综合设计步骤,并提供了氧化铝陶瓷基片的一些强耦合特性曲线和放大尺度单线阻抗(?)线宽特性。对耦合度为3～30db的四分之一波长定向耦合器的综合设计,给出了计算结果。     

Brown＇s Blossom in Britain-China

The overall strategic relationship between U.K. and China is ＂better than ever＂, China- Britain relations have maintained good momentum, with increased high-level exchanges and the reinforcement of strategic mutual trust, with more room for growth in the future.     

Challenge and Opportunity Go Hand in Hand——What Global Economic Agitation Brings to the China's Economy?

Domino effects of the global finance agitation As the origin of the subprime crisis,US financial institutions lost USS45 billion last year,accounted for over half of the total US,EU & Japan loss.Since January 15th,Chtigroup released its financial statement of the 4th quarter,showing a net deficit of USS9.83 billion,which marked the hisoric high of its quarterly deficit.     

Jean-Pierre Duprieu： Willing to Be A Legate of Sino-French Business

Estaing, former French president, Valery Giscard d＇Estaing attended Sino-French Economic Seminar held in Shanghai in early April and said that the world center has shifted from the west to the east with many European and US companies entering into Asia, and China has the ability to play an important role in the world stage. Estaing, naming himself＂French Confucian＂, then said in Chinese that a cook-group includes 10 people in ancient Chinese soldier system and the cook is in charge of cooking for them. And people who belong to the same cook are actually ＂Partners＂.     

China''''s Stock Market Wave

The annual meeting of the World Economy Forum was held in Davos,a little town in Switzerland,on January 23rd to the 27th this year,with the theme"the Power fo Collaborative Innovation",over 2500 celebrates from ture political and cconomic circles of more than 80 countries and challengred logether to talk about the future of the global economy in 2008,A Forum for the problems and challenges that face whole world,some of the keywords which drew attention during the event were:the U.S.subprime mortgage crisis,soaring energy prices,the economic slowdown in the U.S.ermerging economic bodies,authority funds and the general unpredictable nature of the global economy.     

Trade Promotion from Neighborhood

If you are considering to trade with companies in Japan or expanding your .business to Japan, we are ready to help from the very beginning.＂ You will find this greeting at the first sight on the Chinese website of Japan External Trade Organization （JETRO）. JETRO has committed itself in delivering highly efficient and quality services to meet the demand of internal and external customs including Japanese companies, hence winning a good reputation in the international trade arena. In recent years, with its priority in advancing business cooperation in South and East Asia, JETRO has made great achievement in promoting trade between China and Japan. Therefore, China＇s Foreign Trade interviewed Mr. Yoichi Maine, Deputy Director General of JETRO BEIJING.     

Auto Parts Market Potential Coming into Surface

Looking at the increasingly fierce competition in the world auto market. global automobile manufacturing industry, taking Europe, the U.S. and Japan as representatives, is gradually forming a new type of relationship, mutual cooperation between whole vehicle and parts manufacturers. We can clearly see that auto parts manufacturers have become independent from the whole vehicle manufacturing companies, which means that the former structure of auto industry has greatly changed, and a new relationship,     

Sinosteel：Extraordinary Moves in Industry Chess

Among the Fortune 500 firms,more and more images from China emerge out.On the 2008 list,Sinosteel Corporation,a landmark group of China industries quietly squeezes into the candidate line.As the largest steel service ＆ trade enterprise,its sales reached at RMB 111.24 billion,with a year-on-year increase of 83.03 percent,and the profit grew by 180.03 percent.On the Sinosteel 2008 Work Meeting,the president Huang Tianwen uttered,＂In the coming year,we will work for US$20 billion sales,and look forward to getting a position in Fortune 500 firms for ourselves.＂     

Walk Through Unusual Five Years—— An Exhibitor＇s Canton Fair Course

When the 103rd Canton Fair is approaching, an old friend of Canton Fair, Li Ying from Jiangsu prov-ince recollected his past five years＇ experiences to the grand trade meeting. Each year is special, with some unforgettable memories colored by the year.     

Public Financial Expenditure——A Reflection of the Livelihood Improvement

In recent years.China's public finance put social construction high on the agenda and attaches more importance on livelihood insurance and improvement.The 2003-2007 public financial expenditure reflects a fact that the government isputting more emphasis on livelihood andissues concerning the people.     

Voices from the MPC and CPPCC

"Crucial for economic growth.energy utilization has its role in all economic sectors and every aspect of people's daily life.Now we are in dire need of a new profession,namely energy manager.We not only need to have passion and responsibility,but also a scientific approach to conserve energy and cut emissions.APpropriate legislation should be in place.and a special profession should be introduced to ensure the implementation of these laws and regulations."