Coherent detection of orbital angular momentum in radio

TL;DR

This paper demonstrates the experimental generation and coherent detection of orbital angular momentum in radio beams using simple electric dipole antennas, opening new avenues for radio communication and sensing technologies.

Contribution

It introduces a method for generating and detecting radio OAM beams with standard antennas, enabling practical applications in communication and remote sensing.

Findings

Radio OAM beams can be generated with ordinary dipole antennas.

Coherent detection of radio OAM is experimentally demonstrated.

Potential applications include advanced communication and sensing techniques.

Abstract

The angular momentum propagated by a beam of radiation has two contributions: spin angular momentum (SAM) and orbital angular momentum (OAM). SAM corresponds to wave polarisation, while OAM-carrying beams are characterized by a phase which is a function of azimuth. We demonstrate experimentally that radio beams propagating OAM can be generated and coherently detected using ordinary electric dipole antennas. The results presented here could pave the way for novel radio OAM applications in technology and science, including radio communication, passive remote sensing, and new types of active (continuous or pulsed transmission) electromagnetic measurements.