Metasurface Cloaking Lens Designed by the Ray Insertion Method

This letter presents a metasurface cloak with the ability to make regions of any shape and size on the flat lens invisible in the microwave band. The gradient refractive index (GRIN) of the metasurface is designed by the ray insertion method, which enables the ray paths of electromagnetic surface waves to be tailored in a desired fashion. The lens is composed of periodic metallic square patches etched onto a grounded dielectric substrate to synthesize the required GRIN of the metasurface. The design technique is validated by simulations using commercial software, which demonstrate the successful bending of impingent waves according to the prescribed paths and thus achieving the desired cloaking effect. A prototype of the GRIN metasurface cloak was manufactured and measured, yielding results that verify the theoretical predictions.