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After that, we focus on the designs and calculations of the ultra-wideband monopole antennas in order to figure out ways to improve the performance of the antennas.

之后，我们重点介绍单极子天线的设计计算方法和改进优化方式，并给出若干设计实例，进行数值仿真和实验的验证。

ABSTRACT In the first chapter, the basic theory and developing phases of spread spectrum communication are introduced. Smart antennas technology is introduced based on comparison of different multiple address methods. The main technical character of smart antennas and the progress in the application are also summarized.

本论文讨论了移动通信CDMA系统中智能天线技术的应用，论文第一章介绍了扩频通信的理论基础及发展阶段，在比较不同多址通信方式的同时引入智能天线技术，归纳了智能天线的主要技术特点，总结了目前智能天线技术在理论和应用中的进展，最后介绍了本文所做的主要工作。

The pair-wise error probability analysis and simulation results show that,under the condition of high SNR,by selecting the set of antennas that observe the largest instantaneous Frobenius-2 norm of received signal vector,the same diversity gain can be achieved as the one obtained by using all the receive antennas.

成对错误概率分析和仿真结果表明：在高信噪比情况下，选择有最大范数的接收天线，系统能实现和使用全部接收天线相同的分集增益。

Numerical results show that network coding can effectively improve the performance of multi-antennas based uplink wireless relay network, and the more the antennas, the better the performance.

数值结果表明，网络编码可以有效地改善多天线上行无线中继网络的性能，并且天线数越多，性能越好。

An antenna designed to have an approximately constant input impedance over a wide range of frequencies; e.g., terminated rhombic antennas and wave antennas.

一种天线，在一个大的频率范围里有近似连续的输入阻抗，例如终端菱形天线和波浪天线。

Many technologies of electrically small antennas and wide band antennas are discussed in theory, simulation and experiment.

在研究中采用了理论分析、数值仿真和实验验证等手段，提出了多种与主题相关的天线结构。

These antennas can cover GSM900/DCS/PCS/UMTS operation. In the chapter 2, the antenna is designed based on the concept of monopole antenna. Furthermore, the antenna structure have two radiant paths and coupled each other at tail end to do impedance matching. In addition, to raise distance between radiation plane and ground will avoid capacitative effect effectually. In the chapter 3, the antenna is designed based on the concept of planar inverted-F antenna. Furthermore, that the antenna structure have two radiant paths and coupled each other at tail end to do impedance matching is similar to chapter 2. But there is a difference in them. We can choose the short position to change input impedance at this structure. In the chapter 4, the antenna is designed based on the concept of planar inverted-F antenna which takes coupled-fed. It will produce the first mode and high-order mode near the frequency, 900MHz. The feature of this type is to reduce the volume effectually. This antenna can not only cover GSM900/DCS/PCS/UMTS operation but maintain good radiation efficiency. Finally, we will compare three antennas, and develop procedure with industrial view, and propose the prospect of the GSM/GPRS antenna in PND, as a conclusion.

在第二章中，我们使用单极天线设计概念，使用双路径架构并於末端耦合来对天线阻抗做匹配，产生涵盖GSM900/DCS/PCS/UMTS四频操作频带，并提高与接地面的辐射高度，以避免电容效应，使天线具有良好的辐射特性；在第三章中，使用倒F形天线设计概念，使用双路径架构於末端耦合，并於辐射臂上采取适当接地点电感效应作输入阻抗匹配，达成涵盖GSM900/DCS/PCS/UMTS系统的四个操作频带；在第四章中，采用倒F形架构并使用耦合馈入方式，使得长辐射金属臂在低频900 MHz附近产生共振，产生低频基频模态及高阶模态，以达成宽频及频宽涵盖GSM900/DCS/PCS/UMTS频带操作，并有效缩减使用体积；最后，分别比较此三种架构的优缺点，再加以业界角度来思考，研发产品天线的流程及思考方向，以及天线应用於可携式导航装置中未来的展望作为本论文的总结。

Especially, discage antennas havesmall electrical size. Discage antennas combine the structure of discone antenna andcone-shape monopole antenna, and make use of ultra-wide-band twin-feed matchingsets.

针对小型化的要求，提出了电小天线的阻抗完全补偿和匹配优化的方法，并将该方法应用在已开发的新型笼锥天线系列上，可将天线工作频率的低端较大地向更低端拓展，从而实现天线进一步小型化。

First, we deduce theoretical formulae of calculating equivalent dielectric constant and resonance frequency of rectangular microstrip antennas with air gaps from electromagnetic field theory based on the modified theory of cavity model. Then, we discusses the radiant principle of microstrip antennas on the base of transmission line theory and analyzes the problem of air gaps how to influence pattern and other idiocratic parameters of a microstrip antenna in detail.

本论文的主要工作是根据修改的微带天线的腔模理论，利用电磁场理论推导了具有空气隙的矩形微带天线的等效介电常数和谐振频率的理论计算公式，同时以传输线理论为基础，论述了微带天线的辐射原理。

Therefore, the uplink cross-pol interference that we meet is normally caused by the polarization angle mismatch of ground transmitting antennas, or serious overdriven of the uplink power at cross-polarization. And the downlink cross-pol interference is normally caused by the polarization angle mismatch of ground receiving antennas.

因此，常见的反极化干扰通常为，因反极化地面发送天线的极化角失配、或因反极化载波的上行功率严重超标而产生的上行反极化干扰，以及因地面接收天线的极化角失配而产生的下行反极化干扰。

It has been put forward that there exists single Ball point and double Ball points on the symmetrical connecting-rod curves of equilateral mechanisms.

从鲍尔点的形成原理出发，分析对称连杆曲线上鲍尔点的产生条件，提出等边机构的对称连杆曲线上有单鲍尔点和双鲍尔点。

The factory affiliated to the Group primarily manufactures multiple-purpose pincers, baking kits, knives, scissors, kitchenware, gardening tools and beauty care kits as well as other hardware tools, the annual production value of which reaches US$ 30 million dollars.

集团所属工厂主要生产多用钳、烤具、刀具、剪刀、厨具、花园工具、美容套等五金产品，年生产总值3000万美元，产品价廉物美、选料上乘、质量保证，深受国内外客户的青睐