Jing, J.-T. ., W. . Song, and X.-Q. . Sheng. “Transformation Optics-Based Antenna for Focusing OAM Beams”. Applied Computational Electromagnetics Society Journal (ACES), vol. 39, no. 09, Sept. 2024, pp. 794-00, doi:10.13052/2024.ACES.J.390905.