High Power Multi-layer Frequency Selective Filters

Frequency selective surfaces (FSSs) find widespread applications as radomes, dichroic filters and components for satellite antenna systems, and have been extensively investigated in the past. Much of the attention in these studies has been focused, however, on the in-band performance of versions of these filters and little progress has been reported on the important aspect of RCS reduction, which requires an accurate modeling of the out-of-band scattering characteristics of the FSSs that can be either single or multi-layered, electrically thick, and spaced with dielectric layers whose parameters may vary from layer to layer. In this effort, we propose to carry out the development of computer codes based on the newly developed Genetic Algorithms applied in conjunction with general-purpose and computationally-efficient FSS analysis software developed over the last decade by RM Associates, that would simultaneously optimize the in-band transmission and out-of-band scattering characteristics of multi-layered frequency selective screens. In addition, truncation, curvature, transition and finite-thickness effects would be capability, that would require accurate computation of near fields, would be handled by codes specially adapted for this purpose.