Abstract: To overcome the poor frequency linearity of the linear frequency modulation（LFM）signal, 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 continuous wave signal generated by direct frequency synthesis（DDS）technology. The system has the advantages 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 dimensional 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.

Key words: Stepped frequency continuous wave, Millimeter-wave, Cylindrical scanning, Imaging