浅析水平扭转M型下滑天线对入口高度及下滑角的影响

Analysis on Threshold Crossing Height and Glide Path Angle by Horizontal Rotating M-type Glide Path Antenna

对于M型下滑天线,对天线作微调能改变近场DDM分布,从而对入口高度产生影响。本文阐述了扭动天线及调整辐射场形的原理。通过扭动上、下天线,定量分析入口高度和下滑角的改变量与扭动距离的依赖关系,并对飞行校验中的实例进行比较。对比扭动对近场(入口高度)和远场(下滑角)的影响。理论计算得出:上天线向跑道方向扭动一定角度,可以明显提高入口高度,向跑道外侧扭动后,入口高度减小;扭动下天线情况则相反,且两者基本都不影响下滑角。因此表明,扭动天线是一种有效改变近场的方法。

For M-type glide path antenna, the entrance height may be changed by rotating the antenna. In this paper, radiation field shape was changed through rotating the antenna. The variation of DDM, threshold crossing height, glide angle were analyzed and compared theory with practice value of flight checking. Calculation indicated that the upper antenna rotated a little to the runway position, and the height increase evidently, and vice versa. While the lower antenna agree at the reserved result. Meanwhile, both behaviors affected the glide angle little. It is demonstrated that the rotating of antenna is an effective method to modify the near-field distribution of DDM.