ASA 127th Meeting M.I.T. 1994 June 6-10

1aSA8. Edge effects in finite gratings of cylindrical scatterers.

Douglas R. Denison

Robert W. Scharstein

Elect. Eng. Dept., Univ. of Alabama, Tuscaloosa, AL 35487-0286

Edge effects in finite arrays are studied via the analysis and interpretation of one canonical geometry---a linear grating of thin circular cylinders. The partial field scattered by each element in a finite array is decomposed into three components: (1) the contribution of the infinite or periodic array, (2) a component due to the presence of the left edge of the array, and (3) a component due to the right edge of the array. The scattered field due to either array edge is derived from a separate analysis of the appropriate semi-infinite array and is interpreted in terms of a decaying wave that is launched from the array end. This solution to the well-posed boundary value problem is numerically verified via boundary condition satisfaction, where the accuracy of the edge-wave decomposition persists for all tested values of element spacing and plane wave incidence angles. [Work supported by NSF.]