Multi-Layered Flat Meta-Lenses for Conical Beam Scanning via Optimization of Geometrical Optics

We present a methodology for the design of multi-layered flat meta-lenses that are fed off-axis based on a numerical synthesis algorithm hybridizing Geometrical Optics (GO) and Particle Swarm Optimization (PSO). In previous work, the algorithm was applied for the design of on-axis fed flat meta-lenses. In this work, we use the algorithm to synthesize off-axis fed flat lenses with circular symmetry thus producing conically scanned beams. Descriptions on how to realize the synthesized lens using metamaterial elements of variable sizes distributed on planar dielectric substrates are provided. Full-wave simulation results of a 10 cm multi-layered flat meta-lens operating at 13.4 GHz fed from various locations along the ring-shaped focus demonstrate the lens conical scanning capabilities.