Augmented Huygens’ Metasurfaces Employing Baffles for Precise Control of Wave Transformations

A new topology for Huygens' metasurfaces (HMSs) is proposed as a means for dramatically simplifying the design of metasurface-based devices. Traditionally, the constituent unit cells for such metasurfaces are designed and optimized with many assumptions such as local periodicity, normal incident rectilinearly propagating excitation, etc. For applications demanding precise wave transformation, it is necessary to further optimize all the cells collectively to compensate for the inaccuracies of these assumptions. For complex designs with many degrees of freedom, this can be extremely time-consuming. In this paper, we propose a new unit cell topology, which intrinsically enforces the aforementioned assumptions, enabling rapid construction of metasurfaces from a library of preoptimized cells without the need for any subsequent tuning. To illustrate the effectiveness of the proposed topology, several devices are designed and verified numerically. For practical demonstration, a wide-angle reflectionless refracting metasurface employing the proposed unit cells is fabricated and experimentally tested.