查询词典 antenna resistance

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。

Firstly, we research the Vlasov antenna with reflector mainly. A new method to calculate the radiation of the antenna is founded with Vectorial Theory of Diffraction, and the corresponding program is made. The reflective characters of Vlasov antenna are studied with Moment Methods, and the results show that the total reflected energy is less than 0.25%. The radiation patterns of the antenna are analyzed, and the formulas to estimate the wave beam parameters and to design the antenna are provided. The feasibility of radiating high-order modes by Vlasov antenna is also discussed and verified. The hermetization of the Vlasov antenna is researched and the results show that with such kinds of hermetization the antenna can work under gigawatt level. The design of the mode converter from TEM to TMoi is studied, which is useful when the TEM coaxial mode is radiated by Vlasov antenna. At last, the flared-end Vlasov antenna is also discussed.

在Vlasov天线方面：用矢量绕射理论建立了天线辐射场的计算模型并编写了计算程序，该程序计算结果在主瓣上与实验测量吻合良好，近旁瓣也基本一致；利用矩量法计算了天线的反射系数，表明该天线有较小的反射，总的能量反射小于0.25％；详细分析了天线的辐射特性，给出了天线辐射波束相关参数的估算公式和天线设计公式；进一步研究和论证了Vlasov天线辐射高阶轴对称模的可行性；对天线的密封方式和功率容量进行了讨论，结果表明在不需很大密封罩的情况下可以获得GW级的功率容量；为了用Vlasov天线辐射同轴TEM模，研究了TEM-TM_(01)模式转换器的设计，得到了一些基本规律；最后，介绍和分析了带有锥形喇叭的Vlasov天线。

The invention comprises an antenna for receiving a satellite broadcasting signal; antenna coupling member. The antenna coupling member includes a coupling pin and a holding part. The coupling pin is electrically coupled with the socket of the mobile communication terminal for enjoying the satellite broadcasting and the said antenna. The antenna coupling member is coupled with the antenna. While the said antenna coupling member is coupled with the socket, the holding part is used for pluggable supporting the mobile terminal.

本发明包括如下几个部分：天线，它可以接收卫星广播信号；天线连接构件，它带有一个用于导电连接可欣赏卫星广播的移动通信终端的插口与上述天线的连接针，所述的天线连接构件结合于上述天线，在上述连接针连结于上述插口的同时，通过把持部可插拔地支撑于上述移动通信终端。

At present, the wireless devices in general to bring the whole antenna, omni-directional radio antenna to the antenna axis, was "donut"-shaped radiation field; directional antenna is highly directional, in the small angle of radiation is totally outside the scope of signals ; the use of removable external antenna equipment can gain antenna, the antenna can not increase in the case of radiated power to increase communication distance.

目前的无线设备一般自带全向天线，全向天线电波以天线为轴，呈"面包圈"状向外辐射；定向天线具有极强的方向性，在小角度的辐射范围外是完全没有信号的；使用可拆卸天线的设备可以外接增益天线，可以在不增加天线辐射功率的情况下增加通讯距离。

When the gas flux is constant, the ratio of reduced resistance is improved with the increase of the water stream velocity. However, the relationship between the gas flux and the ratio of reduced resistance is more complex. When the water stream velocity is constant, if the gas flux is small in contrast, the effectiveness of reduced resistance is not obvious. But when the gas flux increased, the jetted gas will form """"archform"""" which will augment the shape resistance. In this condition, resistance could not be reduced and could even be increased, if the gas flux continues to be increased. So that there needs setting a baffle called step, which introduces the jetted gas into the turbulence boundary layer. In this case, the shape resistance may be fairly great. Besides, the waterline of model has also some effect on the ratio of reduced resistance, which acts on the size of wave. If waterline is deep, the wave could not affect the deployment of microbubble layer, so there is almost no effect on ratio of reduced resistance. However, the wave would affect distributing of microbubble layer under the model so that the gas could leak out from the two sides of model and directly affect the ratio of reduce resistance if the waterline is very small. Whether installing the dashplate or not has also the great influence on the effectiveness the ratio of reduced resistance. From the results of experiment, conclusion is that adding dashplate will greatly improve the effectiveness of reduced resistance.

当喷气量一定时，水流速度增大，减阻率提高；喷气量与减阻率之间的关系比较复杂，速度一定时，如果喷气量较小，减阻效果就比较差，但当喷气量增大的话，喷射出的气体就会形成一个&拱度&，增加了船模的形状阻力，在这种情况下最好采取断阶喷气，把气体引入到湍流边界层中，在这种情况下，船模的形状阻力比较大；船模的吃水对减阻率也有一定的影响，主要表现在波浪大小上，如果吃水较深，波浪影响不到微气泡层的分布，对减阻率不会造成太大影响，如果吃水较浅，波浪就会影响到微气泡层在船模底部的覆盖情况，可能会有部分微气泡从船模两侧泄漏，这样就直接影响到了减阻效果；是否安装压浪板，对减阻率也有较大的影响，从试验结果可以看出，在船模尾部加设了压浪板时，减阻效果明显得到改善。

This article first antenna, microstrip theory, the circular polarization technology, the theoretical discussion, in this based on the microstrip antenna of circular polarization method - corner square microstrip antenna, and has done a design simulation , and then do the design and further research to improve and eventually get a resonant frequency (S11 reflection coefficient corresponding to the minimum frequency) for the 1.5GHz and 1.43GHz, the frequency of circular polarization for the 1.46GHz, S11 is less than -10dB relative bandwidth, the VSWR is less than 2 is about 8.8% relative bandwidth, axial ratio less than 3dB relative bandwidth of about 2.2% of the right circular polarization microstrip antenna design case, which proved very good the circular polarization microstrip antenna theory, also fully confirmed by a square corner design is a practical program, and select the appropriate regulation of sticks is indeed able to improve the performance of the antenna.

本文先对天线、微带理论、圆极化技术等进行了理论论述，在此基础上，提出圆极化微带天线的实现方法——切角方形微带天线，并对此做了设计仿真，后又对这一设计方案做了改进及进一步研究，最终得到一个谐振频率（反射系数S11 的最小值所对应的频率）为1.5GHz和1.43GHz，圆极化频率为1.46GHz，S11 小于-10dB 的相对带宽、驻波比小于2 的相对带宽约为8.8%，轴比小于3dB 的相对带宽约为2.2%的右旋圆极化微带天线的设计案例，从而很好的印证了圆极化微带天线理论，也充分证实了切角方形是一种切实可行的设计方案，而选取合适的调节枝则确能提高天线的性能。

To overcome the drawbacks in the weight and cost of the antenna with the corrugated soft surface, a new patch antenna with patch rings is designed. Its weight is about 1/4 less than the antenna with the corrugated soft surface and it is inexpensive. Good experimental results are obtained. The radiation pattern of the antenna is more rotationally symmetric, and a more reduction on the sidelobe levels of the antenna is achieved as compared to the antenna with the corrugated soft surface. In conclusion, in the present thesis both theoretical and experimental research works have been carried out intensively on patch antennas based on photonic-bandgap structures.

为了克服皱褶软表面天线份量重，加工费用贵等缺点，我们对空气介质的皱褶圆环结构软表面天线进行了改进，将周期分布的皱褶圆环平面化，并保持结构的软表面特性，设计出了一种新的平面圆环结构的软表面天线并进行了实验研究，加工的平面圆环结构天线比皱褶圆环结构天线重量减轻了约1/4，加工费用大大降低，所取得的实验结果显示，该平面圆环结构软表面天线的方向图的轴对称性得到了改善，在俯仰角从0°～-90°的范围内天线H面的波束与E面重合，与皱褶圆环结构相比，天线的旁瓣和背瓣受到了更大的抑制，E面方向图上+120°方向的旁瓣被明显削弱。

Secondly, in this paper, the four typical UWB antennas of TEM horn antenna, log-periodic antenna, biconical antenna and helical antenna are theoretically analyzed and the UWB antenna design methods are generalized and discussed.

其次，本文对TEM喇叭天线、对数周期天线、双锥形天线和螺旋天线四种典型的超宽带天线进行了理论分析，总结并讨论超宽带天线的设计方法和手段。

According to requirements of engineering design, antenna efficiency and broadband impedance match network, conical antenna is defined as unit antenna after comparing the electric apparatus and element forms of cage antenna and conical antenna.

从工程设计角度出发，根据天线效率和宽带阻抗匹配网络要求，在比较笼形和锥形两种天线的电气和结构性能之后，确定锥形天线为单元天线。

In modern specification of handset, there is one about SAR. However, current mobile phone antenna is dipole antenna with omni-directional radiation pattern in azimuth plane. So much better performance of antenna means higher SAR value. Therefore, in order to improve SAR performance, designer may be forced to detune antenna or use resistor. The two methods will reduce efficiency of antenna.

在移动电话的技术规范中往往有SAR值的要求，这给手机天线的设计带来了严峻的挑战，因为现代的手机天线基本上是在水平面具有全向辐射特点的偶极子天线，因此天线的性能越好往往SAR值越高，所以有时为了降低SAR值甚至故意劣化天线的性能。

Listen,point and check your answers.

听，指出并且检查你的答案。

Warming needle is one of effective treatment methods for knee arthralgia aggravated by cold,and it is simple,safety,so it should be developed in clinical acupuncture and moxibustion extensively.

但以本院科针灸门诊在2005年1月—2006年6月期间共收治膝痛患者100余例，经过临床的诊断后，其中施以温针治疗的48例，疗效显著，报道如下。1临床资料本组病例48