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机载跟踪雷达是航空火力控制系统的目标参数测量装置之一。主要用它来量测目标运动参量,即目标的飞行方向与速度。也就是量测目标速度矢量的位置与方向: V_m=V_1+R+R×ω 其中: V_1——载机飞行速度矢量, R——目标线的接近速率, R——目标相对载机位置, ω——跟踪目标线在空间旋转的角速率。因而机载雷达必须测量目标距离（R）及速率（R）以及目标相对载机的方位、俯仰角（μ、ν）及目标线（为跟踪线）的角速度（ω）。 常用的跟踪雷达天线中有称为卡塞格伦式（Cassigrain）天线,它是由抛物面为主反射器,在该主反射面与其焦点间加入了同焦点的双曲面副反射器组成。如图1所示。形成了双反射型天线。其优点是减小天线轴向尺寸,并使馈源设计与波导安置更为灵活。 然而,有种雷达使用了变态的倒置卡塞格伦天线。它是以抛物面反射器形成平面型波陈,而后经平板型反射器偏振极化之后将电波束反射出去的形式。其更改了原双曲面的结构形态,又将馈源倒置于波阵之前。如图2,故称为倒置卡塞格伦天线（Invertedcassigrain）。它正是由抛物面反射后形成入射的平面波,再经平板反射器扭转波束极化方向使电波传播出去,照射目标和接收目标反射回波形成对目标的跟踪。如图3,很明显,在天线?
Airborne tracking radar is one of the target parameter measurement devices of the airborne fire control system. It is mainly used to measure the target motion parameters, that is, the target’s flight direction and speed. That is, the position and direction of the measurement target velocity vector: V_m = V_1 + R + R × ω Where: V_1 - carrier flight velocity vector, R - the target line approach rate, R - target relative carrier position, ω - Track the angular velocity of the target line in space rotation. Therefore, the airborne radar must measure the target distance (R) and velocity (R) as well as the azimuth, pitch angle (μ, ν) of the target relative payload and the angular velocity (ω) of the target line as the tracking line. Commonly used tracking radar antennas are known as Cassegrain (Cassigrain) antenna, which consists of a parabola-based reflector, the main reflector and its focal point by adding the same focus hyperboloid sub-reflector component. As shown in Figure 1. The formation of a dual reflective antenna. Its advantage is to reduce the axial size of the antenna, and make the feed design and waveguide placement more flexible. However, one type of radar uses a metamorphic inverted Cassegrain antenna. It is a parabolic reflector to form a plane wave Chen, and then by the flat-plate polarizer polarizer beam reflected in the form of reflection. It changes the structure of the original hyperboloid and inverts the feed before the wave array. As shown in Figure 2, so called inverted Cassegrain antenna (Invertedcassigrain). It is formed by the parabolic reflection incident plane wave, and then by the flat reflector to reverse the beam polarization direction of the radio waves out, the target and receive the target reflected echo formation of the target tracking. As shown in Figure 3, obviously in the antenna?