Sidelobe reduction in stepped-frequency-continuous-wave MIMO TWRI of moving targets

Due to the improper time-division multiplexed (TDM) mode, a undesirable sidelobe occurs if the target moves a little fast while a stepped-frequency-continuous-wave (SFCW) multiple-input-multiple-output (MIMO) through-wall radar (TWR) is used to monitor moving targets by real-time imaging. In this paper, we firstly derive the formulas of range shift and pulse spreading due to the target motion, and then we change the TDM mode from switching the transmitting antenna at the end of complete SFCW periods to switching at every frequency, which is very conducive to eliminating the undesirable sidelobe. This modification makes the tracking of higher speed human target possible at a low pulse repetition frequency (PRF).