Microwave and Electromagnetic Laboratory, Harbin Institute of Technology, No. 92, Xidazhi Street, Nangang District, Harbin City, Heilongjiang Province, China.
School of Electronic Engineering, Xidian University, Xi'an, 710071, China.
Sci Rep. 2017 Jan 18;7:40575. doi: 10.1038/srep40575.
Parity-time (PT) symmetric structures present the unidirectional invisibility at the spontaneous PT-symmetry breaking point. In this paper, we propose a PT-symmetric circuit consisting of a resistor and a microwave tunnel diode (TD) which represent the attenuation and amplification, respectively. Based on the scattering matrix method, the circuit can exhibit an ideal unidirectional performance at the spontaneous PT-symmetry breaking point by tuning the transmission lines between the lumped elements. Additionally, the resistance of the reactance component can alter the bandwidth of the unidirectional invisibility flexibly. Furthermore, the electromagnetic simulation for the proposed circuit validates the unidirectional invisibility and the synchronization with the input energy well. Our work not only provides an unidirectional invisible circuit based on PT-symmetry, but also proposes a potential solution for the extremely selective filter or cloaking applications.
在自发破缺的宇称时间（PT）对称点，PT 对称结构呈现出单向隐形。在本文中，我们提出了一种由电阻器和微波隧道二极管（TD）组成的 PT 对称电路，分别代表衰减和放大。基于散射矩阵方法，通过调节集中元件之间的传输线，该电路在自发破缺的宇称时间对称点可以表现出理想的单向性能。此外，电抗元件的电阻可以灵活地改变单向隐形的带宽。此外，对所提出的电路的电磁模拟验证了单向隐形和与输入能量的同步性。我们的工作不仅提供了基于宇称时间对称的单向隐形电路，而且为超选择性滤波器或隐身应用提供了一种潜在的解决方案。
