Garmjani, N. M. ., and N. . Komjani. “Improved Microstrip Folded Tri-Section Stepped Impedance Resonator Bandpass Filter Using Defected Ground Structure”. Applied Computational Electromagnetics Society Journal (ACES), vol. 25, no. 11, June 2022, pp. 975-83, https://journals.riverpublishers.com/index.php/ACES/article/view/15821.