Theory of Reflective Phase-Shifting Surface for Generating Vortex Radio Waves

A theory mainly based on physical optics is developed to analyze reflective phase-shifting surfaces (PSSs) for generating vortex radio waves. The theoretically calculated radiation patterns and phase fronts closely agree with those simulated from a high-frequency structure simulator for the circular disk and annular ring reflective PSS with various dimensions. This theory enables the computation of these surfaces with high efficiency, which indicates its potential for the rapid design and optimization of this important type of surfaces.

I. Introduction

In 1994, Beijersbergen et al. [1] demonstrated experimentally that a spiral phase plate could convert a Gaussian beam into a helical wave front beam with phase singularity at its axis. Since then, optical beams that carry orbital angular momentum (OAM) have been extensively applied in many fields, such as in optical tweezers [2], quantum information [3], and multiplexing in optical communication [4], [5].