Design and realization of planar reflectors through transformation optics

Reflectors are common structures utilized in antenna system to obtain specific directive radiation or to enhance antenna gain. It is quite desirable to construct reflectors with planar or low-profile features in many applications. In this paper, we present the design of two kinds of low-profile planar electromagnetic wave reflectors based on the transformation optics. By employing simple linear coordinate transformations, either a retrodirective reflector or a parabolic reflector can be achieved on planar conducting sheet with dielectric cover composed of homogeneous birefringent dielectric media, which reduces the complexity of practical realization. Such simple designs allow us to further realize the reflectors by alternative layers of normal dielectrics based on the effective medium theory. The practical realizations at microwave regime have been validated by full wave electromagnetic simulation, which also demonstrate broadband performance.