Khalifa, M. O. ., A. M. . Yacoub, and D. N. . Aloi. “Compact 2x2 and 4x4 MIMO Antenna Systems for 5G Automotive Applications”. Applied Computational Electromagnetics Society Journal (ACES), vol. 36, no. 06, Nov. 2021, pp. 762-78, https://journals.riverpublishers.com/index.php/ACES/article/view/12089.