Wideband Beam-Steerable Flat Reflectors via Transformation Optics

A conventional parabolic reflector is converted into a flat one based on the discrete coordinate transformation. Instead of general beam-steering techniques, such as off-axis feeding, tilting the feed/reflector, or utilizing phase shift, we show an alternative way to manipulate the reflected emission through tuning transformed dielectrics. The proposed design, only including the conventional dielectric components, has a merit of keeping the flat profile of a compact reflector system while possessing the ability to steer the radiation beams in a wide frequency band.