Phase analysis of cone scattering near base-on

Theoretical calculations of the amplitude and phase of the horizontally polarized backscatter from a small right circular cone in the region near base-on are presented. Predictions are performed using both the geometrical theory of diffraction (GTD) and the physical theory of diffraction (PTD) and are compared to experimental phase and amplitude data obtained on the Georgia Tech compact radar cross-section range. Discrepancies between prediction and experiment are noted and it is shown that analysis of the phase of the backscatter can provide a clue to the understanding of these discrepancies and can be used to determine the location of scattering centers whose presence may not be apparent in amplitude data. Based on this analysis, the initial GTD formulation is modified by the inclusion of a tip scattering term and the resulting prediction is shown to agree well with experiment.