Energy unidirectional transmission in an asymmetrically finite transmission line
Tao Feng(陶锋), Chen Wei-Zhong(陈伟中), Xu Wen(许文), and Du Si-Dan(都思丹)
Chin. Phys. B . 2012, (1): 14101 -014101 .  DOI: 10.1088/1674-1056/21/1/014101