Micro-Doppler Signatures of Dynamic Humans From Around The Corner Radar

Recent studies have demonstrated the possibility of sensing dynamic targets around the corners with no direct signal in line-of-sight with respect to the radar. These works have mostly focused on the detection of targets around the corner on the basis of multipath scattering from lateral walls. However, strong specular multipath returns are only obtained for highly conductive walls or at high carrier frequencies. There is minimal research effort into using the existing indoor radar hardware at much lower carrier frequencies for around the corner sensing of targets. In this paper, we have performed a detailed experimental analysis, including both simulations and measurements, of the effect of wall parameters and carrier frequency on the around the corner micro-Doppler signatures of dynamic humans. Our results demonstrate that in real world scenarios where walls are lossy, target micro-Dopplers are weak and distorted by multipath scattering at high carrier frequencies and are sensed only very near the radar. At lower carrier frequencies, the targets are sensed at greater distances and the micro-Dopplers are not significantly distorted by multipath since the signals mostly travel along the direct path through the wall.