Electromagnetic Field Fingerprint Method for Circularly Polarized OAM

Orbital Angular Momentum (OAM) as an emerging technique to improve the channel capacity and spectral efficiency has attracted more and more attention. However, this technology has some shortcoming in the wireless field such as strict aligned transmissions and large receiving aperture for long distance transmissions. This paper aims to address these issues by proposing an Electromagnetic Field Fingerprint (EFF) method with circularly polarized OAM beams. Results show that EFF can blindly find the origins of beam center with no extra cost and the proposed method can improve the coverage rate over the classic Phase Gradient Method (PGM). Our work enables the detection of OAM with small apertures in mobility scenarios.