查询词典 antenna

The quadrifilar helix antenna is widely used in the space communication, as it has globe symmetry band and good circular polarization.

四臂螺旋天线由于其优良的圆对称半球波束特性，良好的广角极化特性，在空间通信中得到广泛的应用。

A novel conical printed quadrifilar helical antenna for GPS application is presented.

提出了一种应用于全球定位系统的宽波束圆极化圆锥印刷四臂螺旋天线。

The paper studies a quadrifilar helix antenna with good radiation property and proposes a new one.It has four feed ports and the phase difference between two borders upon ports is 90 degree.

K ilgus在1968年提出的谐振式四臂螺旋天线[1]具有一些引人注目的特点，该天线通过选择适当的物理尺寸以及馈电方式可以形成不同的辐射方向图；此外它还具有重量轻、尺寸小、不需要参考地的优点。

A Quadrifilar Helix Antenna is adopted for the platform positioning and a horizontal monopole using the cylindrical wall of the cavity as its ground is adopted for communication.

定位天线采用四绕螺旋天线；通信天线采用以腔壁为地的水平单极振子。

quadrifilar helix antenna ; circular-polarization ; axial ratio

它有四根旋臂和顶部的两根直臂，每根旋臂的旋转角

The aspect of discuss in this paper such as anisotropic dipole antenna radication field numeral calculation and wave parameter calculation has little documentation systematic introduce at the present.

在研究过程中，涉及到复宗量贝塞尔函数的数值计算，由于它对本文的结果影响较大，且各种数学手册无虚宗量贝塞尔函数值可查，所以对其进行了较为详细的研究。

ATbstract: he small frequency modulated transmitter, the power is small, may launch the wireless signal, accepts the signal with the radio, satisfies certain transmission range, Circuit easy system, low cost, power output does not exceed 5-8 mW, firing range to be in the housing area of about 100 meters, with an ordinary FM radio receivers, demonstrating his superb sensitivity and clarity, the most circuit design challenges of the part is only used 3 V power supply, and half-wave antenna will be such a launch capability.simultaneously can input the sound signal, may install modulation surveillance table to serve as the monitoring device, although the power is not very big, but should the interference protection normal radiobroadcasting signal.

小型调频发射机，功率小，可以发射无线信号，用收音机接受信号，满足一定的发射距离。电路简单易制，造价低廉，输出功率不超过5－8mW，发射范围在房屋区可至100米左右，用一部普通的FM收音机接收，显示其灵敏度和清晰度俱佳，电路设计中最富挑战性的部份就是只需用3V电源和半波天线便有如此的发射能力。同时能够输入声音信号，可安装调制监视表头用作监视器，虽然功率不是很大，但是应该防止干扰正常的无线广播信号。

A cross shaped sum-difference network is constituted by microstrip ramose coupler with compact structure and calculated by ADS,while the 8×8 rectangular patchs,which is optimized by HFSS on basis of the method of parameter load and so on,form the transmiting/receiving antenna.

采用新型平面微带型和差网络实现了Ku波段单脉冲天线阵列的小型化设计。

A cross shaped sum-difference network is constituted by microstrip ramose coupler with compact structure and calculated by ADS,while the 8×8 rectangular patchs,which is optimized by HFSS on basis of the method of parameter load and so on,form the transmiting/receiving antenna.

使用ADS优化设计了一种结构紧凑的&十&字形和差网络，并且使用参数加载等方法，在HFSS中仿真出一个8×8的微带矩形贴片天线阵列作为收/发天线，和差网络和微带天线阵列组成单脉冲天线阵。8×8天线阵列、和差网络和馈电系统在同一平面上，所以此天线阵列与传统单脉冲阵列相比体积更小，结构更紧凑，对该天线阵列进行了研制和测试，测试结果符合设计要求。

In anFDD wireless system, the duplex spacing between uplink and downlink islarger than the coherence bandwidth of the mobile radio channel, thus theuplink and the downlink small-scale fading is uncorrelated. Moreover, thearray response is correlated with the frequency of the signal carrier. So it isimpossible to resue the uplink weights for downlink beamforming. As aresult, the application of smart antenna for the downlink is a difficult problem.

在频分双工系统中，由于上、下行载波的频率差大于相干频带，上、下行信道衰落是不相关的，而且阵列响应也与信号的载波频率有关，因此，上行信道不能直接用来估计下行信道，故智能天线应用于下行链路是一个难点。

The use of the web to spread fears that flicking the switch on the LHC could create a Black Hole that could swallow up the Earth particularly concerned him, he said.

他说，使用互联网散布恐慌说启动LHC会生成一个可能吞噬地球的黑洞的做法让他感到忧虑。

Not a single word have I written down.

我一个字也没有写下来。