基于焦面场的多波束反射面天线二维DOA估计

Two-dimensional DOA estimation for multi-beam reflector antenna based on focal-plane field

利用致密焦面阵列馈源,通过二维来波方向(direction of arrival,DOA)估计算法判别干扰信号的方向,是多波束反射面天线设计中的一个重要环节。由于阵列馈源接收的信号由源信号在反射面焦平面上的电场决定,其阵列流形与常规DOA估计平面阵列的阵列流形不相同;焦面场一般是不均匀的,因此选用的阵列单元接收的信号幅度也不相同,部分阵列单元接收的信号会比较微弱;不同的焦面场选用的阵列单元不同,对应的阵列结构也不相同,且其往往是不规则的;源信号经过反射面反射后,阵列单元接收的信号之间的相关性会降低。这些因素决定了阵列馈源的DOA估计具有特殊性。因此结合焦面场,设计了多波束反射面天线二维DOA估计方法,并进行了仿真,仿真结果证明了该方法的有效性和实用性。

It is one of the important design processes in multi-beam reflector antennas to detect the direction of the interference signals by the two dimensional direction of arrival(DOA)estimation algorithm with dense focal-plane array feed.Because the signal received by elements of the dense focal-plane array is determined by the focal-plane electric field of source signals,the array manifold of array feed is different from that of the conventional DOA planar array.The focalplane field usually distributes uniformly;consequently,the signal strengths of array elements are different among each other and some of them are weak.Different array elements are adopted for different focal-plane fields.As a result,the array structures are not fixed and always are irregular.The correlation between the received signals of array elements will decrease after the reflection of the sourcesignals by the reflector.All these factors determine that the DOA estimation of array feed has special features,so a two dimensional DOA estimation method combining the focal-plane field for the multi-beam reflector antenna is proposed,and the simulation results validate its effectiveness and practicability.