基于步进频连续波的近距离主动毫米波圆柱扫描成像系统

摘要

为了克服压控振荡器( VCO)输出线性调频( LFM)信号频率线性度较差的缺点，本文提出了基于直接数字合成( DDS)技术产生步进频连续波信号的近距离主动毫米波圆柱扫描成像系统，该系统具有距离分辨率高、频率精度高以及波形产生和波形控制较为简单的优点。首先，本文通过步进频连续波信号的探测原理分析了该信号的一维距离像、距离分辨率以及距离模糊的特点；然后，通过波动方程推导出近距离主动毫米波圆柱扫描成像系统的重构算法；最后，在微波暗室搭建了半实物仿真成像系统，验证了步进频连续波信号在近距离主动毫米波圆柱扫描成像系统中应用的可行性和有效性。%To overcome the poor frequency linearity of the linear frequency modulation( LFM) sig-nal, which generated by voltage-controlled oscillator(VCO). This paper presents the near filed active millimeter-wave cylindrical scanning imaging system, which is on the basis of the stepped frequency con-tinuous wave signal generated by direct frequency synthesis( DDS) technology. The system has the advan-tages of the high range resolution, high frequency accuracy and waveform generator and waveform control relatively simple. First, by the detection theory of the stepped frequency continuous wave signal, one di-mensional range profile, range resolution and range blurring of the stepped frequency signal are analyzed. Second, through the wave equation the reconstruction algorithm is deduced in near field active millimeter-wave cylindrical scanning imaging system. Finally, the semi-physical simulation imaging system is set up in the anechoic chamber to verify the feasibility and effectiveness of the stepped frequency continuous wave signal applied in near filed active millimeter-wave cylindrical scanning imaging system.