A sidelobes/grating lobes suppression method for ultrawindeband ultrasparse array through-the-wall imaging radar

Ultrasparse array based through-the-wall imaging radars employing stepped frequency continuous wave are faced with high range sidelobes and lateral grating lobes. Range sidelobes are usually reduced by windowing at the expense of lower range resolution and stronger lateral grating lobes. Phase coherence factor (PCF) can suppress lateral grating lobes but fails to mitigate range sidelobes. If we weigh the windowed image by PCF to combat range sidelobes and lateral grating lobes, range windowing will raise the grating lobe level and thus degrade the PCF performance. To solve this problem, we propose a method based on PCF combined with dual apodization (DA), which can suppress both range sidelobes and lateral grating lobes efficiently. Simulation and experiment results demonstrate the validity of this method.