Hai-Tao Chen, Rui Pan, Wei-Zhong Sun, and Si-Yuan He. “Microstrip Reflectarray for Generation of Electromagnetic Waves With Beam Vorticity”. The Applied Computational Electromagnetics Society Journal (ACES), vol. 33, no. 05, July 2021, pp. 488-93, https://journals.riverpublishers.com/index.php/ACES/article/view/9149.