Experimental Study of Shadow Region Imaging Algorithm with Multiple Scattered Waves for UWB Radars

Ultra-wide band (UWB) radar holds high range resolution in the near field sensing, and is thus applicable to security systems designed to identify a human body even in invisible situations. Although Synthetic Aperture Radar (SAR) creates a stable and accurate target image for such applications, it often suffers from increased shadow regions in the case of complex or multiple targets. On the contrarily, a multiple scattered wave has the potential to enlarge a visible range because it propagates a path, that differs from that of a single scattered wave. While various algorithms based on time-reversal processing with multiple scattered waves have been developed, these require a priori information of the surroundings or a target model. This paper proposes a shadow region imaging algorithm based on the aperture synthesis of multiple scattered waves, that can directly increase the visible area and is applicable to arbitrary target shapes. This algorithm reconstructs a target image by synthesizing a double scattered wave according to its propagation path. The results in numerical simulations and an experiment verifies the effectiveness of the proposed method that it directly makes a shadow region visible without a preliminary observation. 1