偏轴卡塞格伦天线的二次赋形

针对采用旋转副镜方式切换频段的大型卡塞格伦天线,提出根据等光程条件和主反射镜的射线描迹对副反射镜进行二次赋形,以修正偏轴对光程造成的影响。通过物理光学法计算了二次赋形后的卡塞格伦天线及正馈和偏焦的对称型卡式天线远场方向图,并比较了馈源相心在不同横偏距离时二次赋形后的天线方向图。结果表明:副反射镜的二次赋形有效地修正了偏轴对天线辐射方向图的影响。

Design for re-shaped Cassegrain antenna with offset feeds

In this paper,an efficient method is presented for correcting the phase difference due to the offset feeds illuminating the large Cassegrain antenna in which feed switch is realized by rotating its sub-reflector.Equations for solving the geometrical parameters of the new sub-reflector based on equal optical distance condition and Snell law are derived.Radiation patterns are calculated for the case with a symmetrical sub-reflector and the case with an asymmetric one.Comparisions are made between the two case...