Fanti, A. ., G. . Montisci, G. . Mazzarella, and G. A. . Casula. “Effective Analysis of Ridged Circular Waveguides With a Curvilinear Frequency-Domain Finite-Difference Approach”. Applied Computational Electromagnetics Society Journal (ACES), vol. 28, no. 11, Sept. 2021, pp. 1100-1, https://journals.riverpublishers.com/index.php/ACES/article/view/11325.