AXISYMMETRICAL MONOSTATIC AND BISTATIC RESONANCE EXCITATION MECHANISMS OF LARGE ASPECT RATIO TARGETS - IMPULSE EXCITATIONS AND BIPOLAR COUPLINGS

An experimental/theoretical study of the scattering from large aspect ratio, finite elastic cylinders is presented. The study focuses on the excitation mechanisms of the axisymmetric resonances. It is found that significant coupling of the incident field to these resonances occurs in the region of geometric shadow at low kD/2 (D is the cylinder diameter). The implications of this coupling for the relative excitation strengths of the resonances and for the associated bistatic beam pattern are examined. It is argued on physical grounds that the results must apply to all large aspect ratio targets (both solids and shells).