Generation of conical beam by reflective metasurface

Abstract

We use the phased-array model to theoretically analyze the conical beam-shaping. It shows that the cone angle of the conical beam can be arbitrarily controlled by just changing the initial phase excitation distribution on the array. Based on this mechanism, a passive reflective metasurface is designed to generate conical beam with certain cone angle. The metasurface element, designed based on the concept of geometric phase, is composed of two orthogonal I-shaped metallic structures etched on a back-grounded dielectric substrate. Under the normal illumination of left-circularly polarized incidence, left-circularly polarized conical wave can be obtained at 15.5 GHz with a cone angle of 13.6 degree. Simulation and measurement are carried out to validate the theoretical prediction, which show good agreement with each other.