A Huygens' metasurface lens for enhancing the gain of frequency-scanned slotted waveguide antennas

Lenses at the microwave/millimeter-wave frequencies can be used to improve the performance of antennas. However traditional dielectric lenses suffer from high reflections and large physical thickness. To combat these issues, we propose a Huygens' metasurface lens design which can perform the desired lensing effects while minimizing reflections and keeping a low profile. The proposed metasurface utilizes a wide variety of unit cells to accurately model the theoretical boundary conditions necessary for a focusing wave transformation. An example of a metasurface cylindrical lens is designed to improve the gain of a 40λ long frequency-scanned slotted waveguide antenna operating in the frequency range of 33.4GHz to 35.2GHz. The proposed metasurface is designed to increase the gain of the feed antenna while maintaining its scanning capabilities.