Xida Deng, Kai Da Xu, Zhigang Wang, and Bo Yan. “Novel Microstrip Ultra-Wideband Bandpass Filter Using Radial-Stub-Loaded Structure”. Applied Computational Electromagnetics Society Journal (ACES), vol. 32, no. 12, July 2021, pp. 1148-51, https://journals.riverpublishers.com/index.php/ACES/article/view/9413.