Design of Dielectric Structures with Nonuniform Holes Optimized for Backscattering Reduction

We present design and optimization of three-dimensional dielectric structures that provide efficient backscattering reduction (BSR). Although BSR is a subject involved in a plethora of applications and is studied intensively in the literature, the complexity of the designed structures often leads to challenges in fabrication and production phases. In this study, very effective BSR is achieved with relatively simple dielectric geometries using only a single material and air-filled holes. Moreover, with the designed structures, BSR can be achieved not only in a single frequency range but also in two frequency bands. All structures are solved and analyzed by the multilevel fast multipole algorithm (MLFMA) and optimizations are successfully performed by combining this method with genetic algorithms (GAs). By optimizing the size, arrangement, and depth of holes on dielectric structures, backscattering from a metal plate can be reduced by as much as 37 dB.