基于子阵时延的数字阵列宽带波束形成

Using Fractional Delay in Subarray to Realize WDAR Beamforming

数字阵列雷达是雷达发展的重要方向之一。在宽带信号下,由于孔径效应影响,传统的波束形成方法会导致天线波束指向不准和主瓣展宽,为此需要使用时延补偿单元取代传统窄带相控阵中的移相单元。文中以均匀线阵为模型,分析了瞬时带宽理论,并引入了分数时延滤波器的时延方法,实现数字阵列收发传输时延的精确补偿。仿真结果表明:在线阵中,对每个子阵采用分数时延滤波器进行数字波束形成,有效地解决了宽带信号波束图指向偏移,主瓣展宽的问题。

Wideband Digital Array Radar（WDAR） is an important development trend of radar. In wideband signal, the traditional phase-shift method causes pattern pointing deviation and mainlobe widening, so the true time delay should be used to compensate the channel dispersed delay accurately. This paper analyzes instantaneous bandwidth theory and introduces fractional delay filter（FDF） design which is used to realize true time delay. The simulation result indicates that, in line arrays, using FDF in every subarray to realize DBF can solve effectively the pattern pointing deviation and mainlobe widening problems.