Sun, Y. ., G. . Wen, H. . Jin, P. . Wang, Y. . Huang, and J. . Li. “Wide Bandwidth Endfire Antenna With Log-Period Directors”. The Applied Computational Electromagnetics Society Journal (ACES), vol. 30, no. 11, Aug. 2021, pp. 1173-9, https://journals.riverpublishers.com/index.php/ACES/article/view/10331.