Realizing a Flat UWB 2-D Reflector Designed Using Transformation Optics

This paper presents the design and experimental validation of a flat ultra-wideband 2-D reflector designed using transformation optics (TO). The flat TO reflector mimics the electromagnetic characteristics of a curved parabolic reflector that is rotated about its apex to reflect the incident wave to a prescribed direction. The TO reflector is true-time-delay (TTD) in nature and it offers a very large bandwidth which is theoretically unconstrained. The proof-of-concept TO reflector design is explored by employing an effective material with an inhomogeneous electric response which is realized by an array of dipoles. We experimentally verify the principle of operation of the reflector over a 67% bandwidth and show that it maintains good radiation characteristics and low beam squint. The design considerations, benefits and drawbacks of the proposed TO reflector are discussed.