天线

The key for phased array antennas with good functions is the use of controllable phase shifters.

其中可控数字移相器的使用，是相控阵天线优越性能实现的关键，但由此引入的相位量化误差，严重影响了相控阵天线的波束指向精度。

Furthermore, we find that for MIMO systems with constant number of scatterers, increasing number of antennas cannot linearly increase the capacity.

更进一步的说，我们发现了对於一个具有固定数目的散射体的多重天线系统，增加天线的数目并不能使得容量呈现线性的增加。

Reflecting objects or targets intercept and reradiate a portion of the radar signal;asmall amount returns in the direction of the radar and is collected by the antenna.

雷达信号(其形式通常为重复的短脉冲序列)由发射机产生，通过天线发射，反射物拦截并反射部分雷达信号，其中一小部分向雷达方向反射回来，被天线接收。

Theradar signal,usually in the form of a repetitive train of short pulses,is generated by a transmitter and radiated into space by an Bed / Night Stand or targets intercept and reradiate a portion of the radar signal;asmall amount returns in the direction of the radar and is collected by the antenna.

雷达信号(其形式通常为重复的短脉冲序列)由发射机产生，通过天线发射，反射物拦截并反射部分雷达信号，其中一小部分向雷达方向反射回来，被天线接收。

New type radar of aerial series developed by Chinese Electron Scientific and Technological Company 38th Institute adopted the design plain of level array aerial which is layered by digital array unit.

中国电子科技集团公司第38所研制的某新型雷达天线系列采用了数字阵列模块拼装平面阵列天线的设计方案。

Among them is, for example, the coffee can antenna that has gain of about 6-7 dBi and is very inefficient as a feed for offset parabolas.

它们是，例如，咖啡筒天线有大约6-7dBi的增益，做偏馈抛物面天线的馈源是非常低效的。

The addition of director element in 2 element bi-quad feeds gave high values of efficiency of illumination of offset parabolas.

叠加双菱馈源天线增加的引向器给了偏馈抛物面天线更高的照射效率。

A 3D corner reflector antenna, with dimensions of 1.7 wavelengths, still has too narrow a vertical diagram and is suitable only for very shallow offset parabolas, with F/D of about 1 and more.

一个尺寸为1.7波长的3D角反射器天线，垂直方向图非常狭窄，只适合很浅的偏馈抛物面天线，其F/D大约1或者更多。

It is obvious that 3D corner reflector antenna could be also adjusted for offset parabolas with a lower F/D if the diagram could be widen in vertical plane and narrowed in horizontal plane so that they are approximately equal to each other and at the same time retain all other good characteristics of this antenna.

显然，3D角反射器天线也必须调整才能用于低F/D的偏馈抛物面，如果它的垂直方向图必须宽，水平方向图必须窄，那么垂直和水平两者之间必须大体平衡，而同时要保持天线的其它所有良好特性。

Introduction 引言 The problems that occur while illuminating shallow offset parabolas, in addition to those related to the efficient use of parabolic generally, are additionally aggravated by the specific geometry of the parabolic mirror itself.

这个问题时常存在于浅照射的偏馈抛物面天线上，除了和抛物面天线的效率有关之外，抛物线反射面本身的具体几何形状又使之更加严重。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。