Strong backscattering enhancement for partially convex targets in random media

Earlier work pointed out that the radar cross section (RCS), owing to the d ouble-passage effect on waves propagating through random media, is enhanced by a factor ranging from one up to three. However, our study has manifeste d numerically a strong enhancement in RCS of targets with concave-convex su rfaces in continuous random media, by taking account of boundary conditions of waves on targets. We have found that when a plane wave illuminates a co nvex portion of the concave-convex conducting target in a random medium, th e factor of enhancement oscillates about two with target size. Moreover, th is enhancement becomes quite large at certain target shapes and also under a specific condition of target size and spatial coherence length of the inc ident H-wave. The large enhancement is considered as an anomalous feature i n the behaviour of backscattered waves in random media. By analysing the sc attering problem for beam-wave incidence on the same target in free space, we manifest the mechanism of such anomalous enhancement.