基于焦面场的多波束反射面天线二维DOA估计

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。

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

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.