一种单层双频宽带GNSS测量型天线设计

基于单介质层结构,设计了一款双频宽带全球卫星导航系统（GNSS）测量型天线,天线采用单层高性能轻质复合材料作为双频微带天线共用的辐射介质基板。双频辐射贴片单元采用共面齿轮结构设计,并在天线单元外围设置一系列短路销钉来有效改善天线轴比带宽、低仰角辐射增益等参数,四馈点馈电技术和宽带耦合相移馈电网络的应用保证了天线相位中心稳定度更加可靠。设计结果表明,该双频天线单元大于等于5 dBi的辐射增益带宽均大于245 MHz,高低频3 dB轴比带宽分别为-76°~76°和-116°~116°,低仰角90°增益滑落均小于11.5 dB,经实物样机对比测试分析,实测结果与仿真结果基本吻合。实测频谱显示,该天线工作频段覆盖目前在运行的四大导航系统全部工作频点,较好满足GNSS精确测量与定位系统终端设备应用需求。     

一种单层贴片式双频双极化滤波天线

设计了一种单层式跨频段双频双极化滤波天线。该天线在同一平面上的高频低频辐射贴片共用一个馈电端口，且均可以在两个垂直方向馈电实现交叉方向的线极化辐射。该天线通过在馈电点与低频辐射贴片之间插入一个低通滤波器，明显提高了高频辐射贴片的交叉极化隔离度。研究结果表明，带滤波结构的天线在两个频率点的反射系数小于-20 dB，4.9 GHz的最大增益大于4.8 dBi，26 GHz的最大增益11.7 dBi，〖JP2〗两个辐射频率的辐射方向图均体现良好的线极化特性，且主极化比交叉极化大20 dBi。该天线可作为未来微波与毫米波共用的5G通信终端天线或5G通信基站的MIMO天线阵元，相关技术和结论对于研制一体化集成的双频交叉极化相控阵天线也有重要参考价值。     

采用新型馈电结构的双频宽带导航天线设计

基于新馈电结构,设计了一款覆盖全球四大卫星导航系统的双频宽带贴片天线。采用了一种四分八馈电线路,以8个同轴馈电探针两两相连的方式将两路天线馈电信号合为一路,有效简化了馈电网络的复杂性,同时保证了天线辐射的增益、带宽和轴比性能。该双频辐射贴片单元采用正八边形层叠式结构设计,并在每个天线单元边缘对称添加两组矩形调谐单元,有效增加了天线辐射的波束带宽。该双频天线单元在高频1.482~1.617 GHz（波束带宽155 MHz）和低频1.191~1.252 GHz(波束带宽61 MHz）频段范围内,都能保证良好的辐射增益;高低频的3 dB轴比带宽为-130°~130°,具备良好的圆极化性能。经实物样机对比测试分析,实测结果与仿真结果基本吻合。     

一种改进的小型化超宽带平面倒锥缝隙天线

提出了一种改进的超宽带平面倒锥缝隙贴片天线,通过调整倒锥缝隙和倒锥贴片的形 状,在更小尺寸条件下,实现了超宽带性能。天线总体尺寸为40 mm×40 mm× 1.5 mm。采用仿真软件分析了该天线的阻抗带宽、辐射方向图及增益特性。结果显示,该 天线的回波损耗小于-10 dB的带宽为2.2 GHz到大于16 GHz,在低频段具有全 向性,在3～14 GHz频段增益随频率的变化在4～7 dB之间。     

共面波导馈电的宽带天线设计

介绍了共面波导天线的性能、设计原理,分析了各个参数对天线性能的影响,通过优 化半椭圆辐射贴片的长短轴半径,设计了一种结构简单的共面波导馈电的小型超宽带天线, 覆盖频段为2.9～10.8 GHz。在此天线的基础上,采用在天线辐射贴片底端依次刻蚀三 组矩形 凹口的措施,使得天线的带宽得到进一步的展宽,覆盖了3～31 GHz频段,阻抗带宽超 过10∶1。加 工了实物并进行了测试,测试结果与仿真结果吻合较好,表明这种展宽带宽方法的有效性。 该天线结构简单,尺寸小,便于集成在多种移动通信系统中。     

带引向器的非对称平衡对拓Vivaldi天线设计

设计了一副改进的非对称平衡对拓Vivaldi天线。辐射贴片外边缘用3阶多项式曲线修正，以实现很宽的阻抗带宽。在天线口径处嵌入一个金属贴片作引向器以改善天线的辐射特性。对辐射贴片引入非对称性，使得E面波束偏离得到进一步补偿。实测结果表明，该天线具有极宽的工作带宽，在2~40 GHz内的增益大于0 dBi，且在15~30 GHz内的增益大于14 dBi；E面的波束偏离在6~40 GHz频率范围内小于3°。该天线具有结构简单、尺寸紧凑（44 mm×98 mm）以及方向图稳定等优点。该天线能够较好地应用于相控阵、超宽带系统等。     

一种小型半U型缝折叠超宽带微带天线

提出了一种四分之一波长半U型缝隙折叠超宽带微带天线。该天线采用短路面加载半 U型缝隙以及折叠辐射贴片的方法,实现了小型超宽带特性;天线的尺寸为18 mm×7. 5 mm×7 mm,相对波长尺寸为0231λg×0096λg×009λg （λg是天线 带宽最低频率对应的介质中波长）。仿真显示,天线的阻抗带宽为393%,仿真辐射方向图 稳定,平均增益4.3 dB。由矢量网络适量分析仪E5071C实测天线模型,天线的带宽为3 86～6.47 GHz,相对带宽为5053%,并且从3.53 GHz到大于8.5 GHz频段上 电压驻波比小于3,相对带宽超过826%。     

一种共形宽带圆极化螺旋天线的设计

为满足共形天线低剖面特性的要求,设计并制作了一种低剖面的圆极化阿基米德螺 旋天线。天线利用单臂阿基米德螺旋结构实现圆极化辐射,并采用同轴探针馈电。实测结果 表明,天线在2～11.4 GHz的频率范围内回波损耗小于-10 dB,轴比小于3 dB 的频率范围为25～8.4 GHz。该天线结构简单,工作频带宽,且剖面极低,可作为多 种载体的共形天线使用。     

宽带小型化U型贴片天线的设计

设计了一副中心频率为2 GHz的四分之一波长U型贴片天线。采用U型槽加载减小了探针 电感,使天线实现双谐振工作,通过将双频比调整到接近为1以展宽天线的工作频带,设计 出的天线的带宽达49%(VSWR<2)。利用短路墙加载技术,使天线的尺寸在四分之一波长 左右 ,减小了天线尺寸,天线的尺寸仅为295 mm×40 mm×12 mm。实际制作了该 天线,测试结果与 理论分析基本吻合,验证了设计的正确性。该天线结构简单,便于设计以及加工制作,同时 方便集成于移动通信设备中。     

基于LTCC的S频段新型耐高温天线设计

基于低温共烧陶瓷（LTCC）技术与传统的贴片天线,设计了一种S频段新型耐高温天线。该 天线充分发挥了LTCC材料良好的耐高温性能,能够承受的最高温度可达400℃左右。通过两层耦合贴片 的设计方法,使天线可以工作在一个较宽的频率范围内,解决了高介电常数引起的窄带工作 和高温导致的谐振频率偏移问题。同时,微带馈线部分通过阶梯阻抗变换,降低了天线的回 波损耗,提高了端口的匹配效率。仿真结果表明,当天线工作的中心频率为2.67 GHz、 工作环境温度为25℃到400℃时,可用带宽为100 MHz,且辐射方向性稳定。     

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.     

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.     

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,     

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."