Modal Purity and LG Coupling of an OAM Beam Reflected by a Rough Surface for NLoS THz Links

Xinzhou Su, Nanzhe Hu, Amir Minoofar, Hao Song, Huibin Zhou, Zhe Zhao, Runzhou Zhang, Kai Pang, Cong Liu, Kaiheng Zou, Haoqian Song, Brittany Lynn, Shlomo Zach, Moshe Tur, Andreas F. Molisch, Hirofumi Sasaki, Doohwan Lee, Alan E. Willner

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

We simulate the modal purities and Laguerre-Gaussian (LG) modal coupling of orbital-angular-momentum (OAM) beams reflected by a rough surface for a non-line-of-sight (NLoS) THz communication link. The reflection of the THz OAM beams is simulated using the finite-difference time-domain (FDTD) method. The simulation results show that: (i) an OAM beam reflected by a metal or dielectric rough surface would experience modal coupling in the 2-dimensional LG modal spectra; (ii) reflected by a metal surface, the modal purities of both transverse-electric (TE) and transverse-magnetic (TM) OAM beams increase as the incident angle increases from 0° to 70° or the carrier frequency of the OAM beams decreases from 1 THz to 0.1 THz; and (iii) reflected by a dielectric surface (n = 1.5), the modal purity and received power of the transmitted TE OAM beam also increase with an increase in the incident angle. However, for TM polarization, the modal purity exhibits a dip near the Brewster's angle. Moreover, with a limited-size receiver aperture, the simulation results for a rough metal surface show that: (i) when the aperture size decreases, the received power of the desired mode decreases by >30 dB while the modal purity of that mode firstly increases and then decreases; and (ii) with the same aperture size, the link could experience ~10 dB higher total power loss and ~12 dB higher channel crosstalk when the standard deviation of the surface height increases from 0.08 mm to 0.20 mm.

Original languageEnglish
Title of host publication2021 IEEE International Conference on Communications Workshops, ICC Workshops 2021 - Proceedings
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)9781728194417
DOIs
StatePublished - Jun 2021
Event2021 IEEE International Conference on Communications Workshops, ICC Workshops 2021 - Virtual, Online
Duration: 14 Jun 202123 Jun 2021

Publication series

Name2021 IEEE International Conference on Communications Workshops, ICC Workshops 2021 - Proceedings

Conference

Conference2021 IEEE International Conference on Communications Workshops, ICC Workshops 2021
CityVirtual, Online
Period14/06/2123/06/21

Keywords

  • orbital angular momentum
  • rough surface
  • spatial-division multiplexing
  • terahertz

Fingerprint

Dive into the research topics of 'Modal Purity and LG Coupling of an OAM Beam Reflected by a Rough Surface for NLoS THz Links'. Together they form a unique fingerprint.

Cite this