Veysi, M. ., and A. . Jafargholi. “Directivity and Bandwidth Enhancement of Proximity-Coupled Microstrip Antenna Using Metamaterial Cover”. Applied Computational Electromagnetics Society Journal (ACES), vol. 27, no. 11, Nov. 2021, pp. 925-30, https://journals.riverpublishers.com/index.php/ACES/article/view/12315.