A study of the analysis and measurements of three dimensional arbitrarily-shaped dielectric scatterers

The objective of this program is to conduct theoretical and experimental research to determine the electromagnetic scattering from heterogeneous dielectric bodies as individual bodies and as a cluster of bodies. The discrepancies in the literature regarding the singularity of the electric dyadic Green's functions were resolved and a unified and consistent view is presented. Compact range scattering measurements at 1 GHz were successfully performed to obtain measured data to validate the numerical analyses. Extensive computations were made for a variety of dielectric scatterers, including a one-foot bird at 1 GHz. The agreements between measurement and computation were good except for the resonant sphere, for which the calculated resonant frequencies were shifted by about 20 percent. Various numerical techniques were investigated successfully for implementation in the volume methods to treat symmetrical scatterers through use of symmetric matrices, the use of banded matrices, and virtual memory. A new local-file manipulation technique for handling large matrices has been explored and found to be potentially useful. There has been very little research into the problem of scattering by dielectric objects of complex permittivity. Future research in this area should include the investigation of the surface integral equation technique and the exact solution for the dielectric prolate spheroid.