星载可展构架式天线方向图快速计算

Fast pattern simulation of deployable truss antenna on satellite

针对可展构架式天线反射面形态的具体特点,在几何光学法的基础上,采用分网积分的方法把抛物面离散,使其在口径面上成矩形网格,在网格内使积分变量分离,再利用菲涅耳积分法求解出单个网格反射后的远场场强,然后叠加所有网格产生的远场得到整个反射面的方向图。通过该算法可以直接根据电性能的要求对构架式天线进行拓扑结构设计,省略了均方根误差这个中间值,使得设计快速直观。用该算法计算一个理想抛物面天线,与Rahmat-Samii等人的结果进行比较,证明该算法精确高效。

The reflecting surface of the truss antenna is composed of triangle element, which causes the deviation from the ideal paraboloid. On the basis of geometry optics, the paraboloid is separated to form rectangular grid on the aperture plane. Then the radiation intensity of the single net can be worked out with Fresnel integration, because the integration variable is separated inside the grid. And the far pattern of the antenna is obtained through synthesizing the far fields produced by all the grids. This computation is applied to an ideal parabolic antenna, which is compared with the results of Rahmat-Samii. It is proved that this computation is precise and effective. A 6m × 2. 5m -aperture truss antenna is designed with the computation as an example produced by antennas with different truss. This provides the most direct basis for the design of the reflecting surface without the Ruze formula to decide the topology grid size of the antenna and its layers