Quasi-conformal transformation electromagnetics enabled flat collimating lenses

This paper demonstrates collimating lenses designed using the quasi-conformal transformation optics technique. The lens can radiate two collimated beams when fed by a simple embedded line source. Thin anti-reflection coatings can be employed to enhance the directive radiation by reducing reflections at the surfaces of the lens. This design only requires spatially-varying dielectric materials with no magnetic properties, facilitating low-loss, broadband operation in both the microwave and optical regimes.