摘要
在基于相控阵馈源的抛物反射面的射电望远镜设计中,增加阵元间距可以扩大视场范围,但会降低视场内灵敏度性能,不能有效提升巡天速度。超方向性天线单元可用于改善这一矛盾,文章将巡天速度指标(SSFoM)作为优化目标,以无限大理想导电平面上的方形口径模拟天线单元,结合解析公式和物理光学方法计算抛物反射面相控阵馈源(PAF)性能,讨论了抛物反射面在不同焦径比(f/D)情况下,天线单元超方向性同SSFoM值、灵敏度、口径效率以及系统噪声温度等性能之间的关系。仿真结果表明,超方向性在提升口径效率的同时,降低了系统噪声温度,提升灵敏度并扩展有效视场。f/D为0.4、0.7和1时,分别设置超方向性系数为1.69、1.37和1.22,可获得最优的SSFoM值,且该值相较于超方向性系数为1时分别提升53%、115%、71%,此时阵元间距分别可以达到0.65λ,0.8λ和0.9λ。
In the design of phased array feed(PAF)radio telescope,larger elements spacing will lead to wider field of view but with lower sensitivity,and fail to improve survey speed.Superdirection unit antenna may do work on this.The paper takes the Survey Speed Figure of Merit(SSFoM)as optimal goal,adapts aperture antenna on infinity perfectly electrical conducting(PEC)plane to act as model of unit antenna,calculates the performs of PAF by using analysis method and physical optics approximation.The paper discusses the relationships among SSFoM,sensitivity,aperture efficiency and system noise temperature by simulating phased array feeds(PAF)with different superdirection and f/D.It is found that the unit with superdirection will lead to higher aperture efficiency,lower system noise temperature,and then follow with higher sensitivity and wider field of view.For the f/D that is 0.4,0.7 and 1,when superdirection is 1.69,1.37 and 1.22,optimal SSFoM increases 53%,115%and 71%,elements spacing is 0.65λ,0.8λand 0.9λ.
作者
陈凯亚
肖阳
CHEN Kai-ya;XIAO yang(The School of Physical Science and Technology,Southwest Jiaotong University,Chengdu 611756,China)
出处
《微波学报》
CSCD
北大核心
2020年第4期43-46,59,共5页
Journal of Microwaves
关键词
射电望远镜
相控阵馈源
视场
巡天速度
radio telescope
phased array feed(PAF)
field of view
survey speed
作者简介
陈凯亚,男,1971年生,博士。主要研究方向:天线理论与技术。E-mail:cky-cy@swjtu.edu.cn。
