Girich, A. A. “Left-Handed Metamaterial Based on the Complementary Split-Ring Resonators Tuned With Varactor Diodes”. Ukrainian Journal of Physics 62, no. 10 (December 12, 2018): 903. Accessed April 26, 2024. https://ujp.bitp.kiev.ua/index.php/ujp/article/view/2018624.