基于阵列排布优化的毫米波高隔离度成像方法

The High Isolation Imaging Method of Millimeter-wave Based on Array Arrangement Amelioration

在密集采样线性阵列中,收发阵元的高隔离度是保证高分辨率近场成像的关键因素之一。针对传统开关切换阵列的毫米波合成孔径成像系统,提出一种基于等效相位中心原则,通过阵列排布方式改善收发隔离度的方法。该处理方式在保证等效阵元位置吻合合成孔径阵列长度的前提下,通过改变收发阵列相对位置、增加收发阵元单次观测时的物理间距实现距离隔离,并结合对等效相位中心误差的分析提出收发阵列最大间隔,以避免收发阵列间隔过大影响成像效果,增强了系统的实用性。最后通过仿真及实验验证,结果表明,与传统阵列相比,该系统隔离度提高了13dB,有效优化了毫米波成像系统的整机性能。

High transmitter-receiver isolation is one of the key parameters to assess performance of array synthetic aperture imaging.This article proposes an amelioration to improve transmitter-receiver isolation by array arrangement based on the principle of equivalent phase center in the millimeter-wave synthetic aperture imaging system with traditional switching array.Under the condition that the equivalent array element position coincides with the length of the synthetic aperture array,this approach increases the sending and receiving physical space within one observation through changing the relative interval to realize the distance isolation.Combined with the equivalent phase center error analysis,it concludes the largest sending and receiving interval array to enhance the practicability of the system in addition to avoid negative imaging effect caused by large space between sending and receiving arrays.Finally,it can be verified that the system isolation is improved by 13dB compared with the traditional array by simulation and experiments,and effectively ameliorated the performance of MMW imaging system.