1. Bao, L., Cui, T.J.: Tunable, reconfigurable, and programmable metamaterials. Microw. Opt. Technol. Lett. 62(1), 9–32 (2020)
2. Antoniades, M.A., Eleftheriades, G.V.: Compact linear lead/lag metamaterial phase shifters for broadband applications. IEEE Antennas Wirel. Propag. Lett. 2, 103–106 (2003)
3. Okabe, H., Caloz, C., Itoh, T.: A compact enhanced-bandwidth hybrid ring using a left-handed transmission line section, in IEEE MTT-S International Microwave Symposium Digest, 2003. vol. 1, pp. 329–332 (2003): IEEE
4. Caloz, C., Sanada, A., Itoh, T.: A novel composite right-/left-handed coupled-line directional coupler with arbitrary coupling level and broad bandwidth. IEEE Trans. Microw Theory Tech. 52(3), 980–992 (2004)
5. Lin, I.-H., Caloz, C., Itoh, T.: A branch-line coupler with two arbitrary operating frequencies using left-handed transmission lines, in IEEE MTT-S International Microwave Symposium Digest, 2003. vol. 1, pp. 325–328 (2003): IEEE