Department of Information Science and Electronic Engineering, Zhejiang University, Hangzhou, People's Republic of China.
Phys Rev Lett. 2011 Nov 11;107(20):205503. doi: 10.1103/PhysRevLett.107.205503.
We studied the active metamaterial transmission line at microwave frequency. The active composite right-handed or left-handed transmission line was designed to incorporate a germanium tunnel diode with a negative differential resistance property as the gain device at the unit cell level. Measurements of the fabricated planar transmission line structures with one-, two-, and three-unit cells showed that the addition of the dc pumped tunnel diodes not only provided gain but also maintained the left handedness of the transmission line metamaterial. Simulation results agree well with experimental observation. This work demonstrated that negative index material can be obtained with a net gain when an external source is incorporated.
我们研究了微波频率下的有源超材料传输线。在单元级，设计了一种有源复合左右手传输线，将具有负微分电阻特性的锗隧道二极管作为增益器件。对具有一个、两个和三个单元的平面传输线结构的测量表明，添加直流泵浦隧道二极管不仅提供了增益，而且保持了传输线超材料的左手性。模拟结果与实验观察吻合较好。这项工作表明，当引入外部源时，可获得具有净增益的负折射率材料。
