Modeling Focused Ray Scattering by a Penetrable Dielectric Slab Over Skin Surface with a Finite Air Gap for Millimeter-Wave Person Scanning

This paper details a model for a weak dielectric object on the human body with a small gap between the dielectric and body, as detected by a CW millimeter-wave security scanning system. This model is a refinement of the Virtual Source Model, focusing on the possibility that the dielectric is not directly against the skin. Seven primary scattering phenomena are considered in this model, more than in the Virtual Source model; later phenomena have negligible amplitude. Even a small gap can cause a significant difference in the return.