| Summary: | Radar cross section (RCS) stealth technology has a major importance in the military applications. In this paper, RCS reduction of metallic sheet is investigated through loading it by dielectric substrate with tapered via holes. The via holes tapering are drilled in two approaches according to the choice of the reference hole radius. In the first approach, the via holes are tapered in a single direction from row to row and are kept fixed along the single
row. A reduction on RCS of 13 dB below the unloaded case is achieved. The RCS reduction frequency band is shifted down by increasing the negative value of scaling parameter due to the reduction of the effective dielectric constant of the dielectric sheet. In the second approach, the holes are tapered along the off-diagonal directions where the tapering occurs along both row and column. A symmetrical structure around the main diagonal is produced. The reduction in RCS is achieved with the band from 11 to 12.75 GHz for different scaling coefficient values with best RCS reduction of 33.5 dB occurs at α=0.18. Symmetrical wide angle RCS reduction from -109o to 109o degrees is reached.
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