Wideband directional-fed holographic metasurface with integrated monopole and parabolic reflector for far-/near-field beams manipulations

Abstract

Abstract Holographic metasurface has been widely investigated, but suffers from the trade-off between bandwidth, gain, and integration. In this article, a wideband high-gain holographic metasurface with miniaturized integrated monopole is proposed. It employs the geometrical characteristics of parabolic reflector to realize directional-fed metasurface, and the footprint is reduced to only one-third of the conventional center-fed designs. By varying modulation index and paraboloid height, the bandwidth and gain are improved simultaneously. To validate the proposed idea, two prototypes are analyzed and fabricated to demonstrate flexible beam manipulation in respective far-field radiation and near-field propagation. Pencil beam pays more attention to the far-field and directionality of the beam, while Bessel beam focuses more on the near-field and non-diffractive of the beam. In both cases, the measured results are well-matched with the simulation. The proposed holographic metasurface for far-field applications features wide bandwidth, high gain, and planar integration simultaneously. Moreover, to the best of the authors’ knowledge, this is the first Bessel beam generator using directional-fed holographic metasurface with parabolic reflector.