Effects of a resistively coated dielectric strip on the TM-polarized resonant backscatter behavior of a slotted conducting rectangular shell

The performance of a resistively coated dielectric strip used to suppress the first TM-type resonant backscatter associated with a two-dimensional slotted conducting rectangular shell is analyzed using the moment method technique. Results obtained indicate that almost perfect resonance damping performances are attained when a finite-sized strip with dielectric constants ∈_r=4-j0.4 and film resistance R_s=188.5 Ω is placed: (1) at the slot (which directly faces the normally incident TM-polarized plane wave), (2) on the interior perimeter of the shell adjacent to the slot, or (3) at the center of the back wall of the shell. Poorer damping performances are observed, however, with the strip placed at other positions and/or with the same or higher film resistance. It is also shown that in general the knowledge of waveguide theory can be used advantageously in the placement of the strip for achieving best resonance damping performance