Geometrical data of dielectric objects from monostatic backscattering


  • Heinz Chaloupka


The first part deals with the scattering problem due to homogeneous dielectric bodies using eigensolutions for the polarization currents. These eigensolutions depend on the shape of the scatterer but are independent on its permittivity. The complex ratio of the electric field strength and current density belonging to the eigensolution is described as a generalized impedance in terms of an equivalent circuit representation. The second part is devoted to the discussion of the backscattered ramp response. An expression is given showing the dependency of the ramp response on the transient behavior of the equivalent circuits. For the case of a frequency-independent permittivity the early part of the ramp response turns out to be approximately proportional to the ‘projected area function.’ Based on this result, algorithms well established for the shape reconstruction for metallic bodies can also be used for dielectric bodies. The last part is concerned with the Rayleigh scattering by bodies exhibiting variable permittivity (e.g., strongly dispersive dielectrics). It is shown that from the knowledge of the εr dependency of the copolar backscattering, the volume and slenderness of the body can be estimated.