Fig. 4: Constellation diagrams and the corresponding recovered images in OAM-based wireless communications.

a–c Single OAM channel with matched and mismatched receivers. d–f OAM mode division multiplexing (MDM) with receiver modes ℓ1 = +1 and ℓ2 = −1. g–i Polarization division multiplexing (PDM) with x-polarization and y-polarization channels. j–l Frequency division multiplexing (FDM) with frequencies 26.8001 GHz and 26.80025 GHz