英文report怎么写 Phased Array Antennas For Mobile Earth
2.1. Early development of phased array antennas
第二次世界大战期间，许多雷达系统的开发基于天线阵列的元素的位置可以产生一个想要或需要的天线辐射模式，如果光束转向要求天线必须机械地移动在所需方向以指导天线主波束。
许多雷达系统的研究工作是由美国的需要跟踪和检测俄罗斯的卫星驱动的。在林肯实验室的特殊雷达组在这一领域，在1950年代后期研究的一个关键的作用，很多成功的作品进行了开发天线单元和相位控制技术，在相控阵天线的发展进一步获得成功[ 3 ]。
During the second World War, many radar systems were developed based on antenna arrays where the element positions could give rise to a wanted or desired antenna radiation patterns, if beam steering was required the antenna would have to be mechanically moved in the required direction so as to direct the antenna main beam.
Much research work on radar systems was driven by the need of the USA to track and detect Russian satellites. The special radar group at Lincoln Laboratories played a key role in research in this field and in the late 1950's, much successful work was carried out in in developing antenna elements and phase control techniques, where further success in the development of phased array antennas was achieved [3].
2.2. Phased array antenna technology
通过添加每个单独的阵列元件的电场强度，可以发现一个阵列结构的整个磁场强度，它被假定在所有的元素中的电流是相同的，并且可以被忽略的天线元件之间的任何相互耦合[ 4 ]。
它已经被一纸[ 5 ] Pozar D M报道如果数组是统一（统一元件之间的间距，均匀的振幅，相位的进展和相同的元素）然后是有效忽略了元素之间的相互耦合。
一个定向辐射模式的产生是实现单个元素的磁场强度将有建设性地加入想要的方向和其它方向的破坏性减。
有一个天线阵列，可以控制在远场的阵列辐射图案的4个关键功能。
天线单元之间的物理距离
天线元件的几何结构
单个天线元件的振幅激励
单个天线元件的相位激励
表2.1控制阵列的辐射方向图的特征。
The entire field strength of an array structure can be found by adding the field strength of each individual array element; it is assumed that electrical current is the same in all the elements, and that any mutual coupling between antenna elements can be neglected [4].
It has being reported by Pozar D.M in a paper [5] if the array is uniform (uniform spacing between elements, uniform amplitude, and phase progression and identical elements) then it is valid to neglect mutual coupling between elements.
The generation of a directive radiation pattern is achieved where the field strength of the individual elements will have to constructively add in the wanted direction and to destructively subtract in the other direction.
There are 4 key features of an antenna array which can control the array radiation pattern in the far-field.
Physical distance between antenna elements
Geometric configuration of antenna elements
Amplitude excitation of the individual antenna elements
Phase excitation of the individual antenna elements
Table 2.1 Features that control the radiation pattern of an array.
