Rotman Lens-Fed Fabry-Perot Resonator Antennas for Generating Converged Multi-Mode OAM Beams

Xudong Bai,Shengyang Xu,Jingyi Qian,Anjie Cao,Weiren Zhu,Chong He,Xianling Liang,Fanwei Kong,Weizhong Yan,Ronghong Jin

doi:10.1109/access.2019.2932199

Abstract

In this paper, we present a Rotman lens-fed Fabry-Perot resonator antennas (FPRA) for generating multi-mode OAM beams with low beam divergence. The Rotman lens works as a beamforming network in the FPRA for the multi-mode OAM operation, significantly simplifying the feed network of the antenna array. The partially reflecting metasurfaces (PRMS) composed of honeycomb complementary hexagonal patches and apertures are designed to construct the Fabry-Perot resonant cavity and enhance the directivity and meliorate the beam orientation of the generated OAM beam. The simulated and measured results verify the effectiveness of the proposed FPRA.

Highlights

Since the first discovery by Allen et al from optical waves in 1992, vortex beams carrying orbital angular momentum (OAM) have aroused enormous attentions in many novel and comprehensive domains, such as quantum entanglement, nanoscopy, astrophysics, and optical communications [1]–[8]
We present a Rotman lens-fed Fabry-Perot resonator antennas to meliorate the multi-mode beams divergence and simplify the feed network for the OAM array
Converged OAM beams with modes l = ±1 and l = ±2 are generated, and the simulated and measured results verify the effectiveness of the proposed Fabry–Perot resonator antennas (FPRA)

Summary

INTRODUCTION

Since the first discovery by Allen et al from optical waves in 1992, vortex beams carrying orbital angular momentum (OAM) have aroused enormous attentions in many novel and comprehensive domains, such as quantum entanglement, nanoscopy, astrophysics, and optical communications [1]–[8]. Dielectric spiral phase plates are introduced to acquire the varying equivalent permittivity around axis through drilling various-size or inhomogeneous holes [16, 17] Major drawbacks with such optical methods are that, only the fixed-mode OAM beams can be created and the structures are very ponderous. A partially reflecting metasurface (PRMS) composed of complementary square patches and apertures was proposed to construct a wideband Fabry-Perot (FP) resonant cavity, but the structure is still with common square lattice, which restricts the isotropy and polarization insensitiveness of the overall PRMS [30]. We present a Rotman lens-fed Fabry-Perot resonator antennas to meliorate the multi-mode beams divergence and simplify the feed network for the OAM array.

STRUCTURE AND MECHANISM

RESULTS AND DISCUSSION

EXPERIMENT AND ANALYSIS

CONCLUSION