非对称副镜卡塞格伦天线辐射场的计算

深空探测天线的多频段特性要求天线能够实现馈源间的快速切换。针对以旋转非对称副镜方式切换频段的大型卡塞格伦天线不再满足原有的口面场分布,利用口面场分布函数积分求解天线远场辐射方法失效的情况,提出了一种计算该型天线的有效方法。给出了一种适合于数值计算的镜面网格划分方法,并利用线性相位近似的物理光学法计算了副镜散射场及天线远区辐射场。计算结果与软件仿真结果的对比表明这种方法是准确实用的。

Farfield Calculation of a Re-shaped Subreflector Cassegrain Antenna

Fast feed switching is indispensable to radiotelescope antennas operating in multiple bands.In this paper,an accurate method is presented for calculating the farfield of large Cassegrain antenna,which realizes feed switching by rotating the asymmetrical subreflector.As the distribution of aperture field has been changed,the classical aperture field method is invalid.An efficient technique for numerical operation is described for replacing the actual surface with a triangular facet representation,and linear phase approximation in Physical Optics is used for getting the radiation performance in the forward axial region.And results indicate that this method is practical.