Multistatic versus Multi-Monostatic Nearfield Millimeter-Wave Imaging of Dielectrics on Ground Planes for Body Scanning Security Sensing

Microwave nearfield imaging is useful for security applications as it safe, non-invasive and penetrates clothing. The phase details of the radar measurements are essential for reconstructing images of metal or dielectric objects which may be hidden on the body. In this paper, we model the body as a flat perfect electrical conductor (PEC) 20 cm in radius. The threat is a cylindrical explosive "puck" 50 mm in radius and 37 mm thick with the dielectric properties of TNT. The body-with-target is probed by 31 millimeter-wave wideband (10-40 GHz) transmitting radar units, each modeled as a right-circularly polarized (RCP) point source, which all lie on an arc in front of the body in the plane of Figure 1 . Thirty-one point source receivers are co-located with the transmitters. The 2½ Dimensional Quasi-Axisymmetric Finite Difference Frequency Domain (2.5D QAFDFD) computational code [1] , which solves the full 3D Helmholtz equation for arbitrary sources in axisymmetric geometries, is used to determine the cross-polarized received fields everywhere in space and particularly in the plane of the arc formed by the sources. This full wave computational tool can accurately model the corner, edge, diffraction and dielectric effects which are not fully captured by ray-based or physical optics methods.