Shielded perfect reflectors based on omega-bianisotropic metasurfaces

We present a novel design procedure for shielded omega-bianisotropic metasurfaces (O-BMSs), fully reflecting a given incident plane wave into a desirable direction, without any spurious scattering. In previous work, we have proven that passive lossless O-BMSs can be designed to support any given field transformation that satisfies local power conservation. Recently, we have relied on this theorem to devise an accurate design of a perfectly-reflecting O-BMS in unbounded medium, harnessing auxiliary evanescent modes to match the intricate power profile formed by the interfering incident and reflected waves. Nonetheless, for many applications, such as radar cross-section reduction, a configuration in which the reflector is positioned near a perfect electrically conducting (PEC) surface is very common. In this paper, we propose a solution that fits this shielded configuration, utilizing auxiliary modes guided between the close-by PEC and the O-BMS to establish local power conservation, allowing a straightforward analytical design of perfect O-BMS reflectors.