FULL-WAVE ANALYSIS OF PERIODIC WEDGE ABSORBER

The performance of radar absorbing material (RAM) is analyzed numerically in low-to-mid frequency range. The dielectric properties of actual absorber were measured and used in the analysis. In the analysis, the so called, Volume-Surface Integral Equation (VSIE) is modified to handle the scattering not only for side incidence but also for forward incidence (i.e., along the wedges). This results in two coupled integral equations in terms of longitudinal electric and magnetic fields. By taking advantage of geometry periodicity, the integration interval is reduced from infinite to one period using Floquet mode expansion. These integral equations are then solved numerically using a point matching technique. The computer code is verified by computing reflection from a lossy slab backed by a perfect conductor and comparing the results to those obtained from exact solution. The scattered fields of infinitely periodic lossy wedges backed by a perfect conductor are computed for a number of cases and the results are presented herein.