Microwave Vortex-Beam Emitter Based on Spoof Surface Plasmon Polaritons

TL;DR

This paper introduces a novel, compact method to generate microwave vortex beams with orbital angular momentum using spoof surface plasmon polaritons, validated through numerical and experimental results, promising for future wireless communications.

Contribution

It is the first demonstration of generating OAM modes using spoof surface plasmon polaritons with a simple, integrable structure.

Findings

Spoof SPPs radiate vortex beams with different OAM modes at various frequencies.

The proposed device is smaller and easier to integrate into circuits.

Numerical and experimental results confirm successful OAM mode generation.

Abstract

Since the orbital angular momentum (OAM) being investigated intensively in the optical region, there are growing interests in employing OAM to solve the problem in wireless communications as a new method. It is found that the independence between different OAM modes is crucial to wireless communications. Motivated by the tremendous potential of OAM in communication systems, we propose a novel method to generate vortex beams by spoof surface plasmon polaritons (SPPs). A looped double-layer spoof SPP waveguide is applied to realize the transmission of electromagnetic waves. Beam emitting is accomplished through a series of circular patches, whose role is not only the radiation units but also resonators giving rise to the phase shifts required by the vortex beam. The proposed method is validated by both numerical calculation and experiment. The measured results show that the spoof SPPs are radiated by the circular patches and the vortex beam carrying different OAM modes are observed at different frequencies. This is the first time to generate the OAM modes by spoof SPPs. The proposed method possesses smaller size and is much easier to be integrated into integrated circuits. The simple structure and design procedure make the proposed method promising in future wireless communication systems.