Exceptional Points of Degeneracy in Periodic Coupled Waveguides and the Interplay of Gain and Radiation Loss: Theoretical and Experimental Demonstration
Exceptional Points of Degeneracy in Periodic Coupled Waveguides and the Interplay of Gain and Radiation Loss: Theoretical and Experimental Demonstration
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周期性耦合波导简并的特殊点以及增益和辐射损耗的相互作用：理论和实验论证
DOI：
10.1109/tap.2019.2922778
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发表时间：
2019
影响因子：
5.7
通讯作者：
Capolino, Filippo
中科院分区：
文献类型：
--
作者：
Abdelshafy, Ahmed F.;Othman, Mohamed A.;Oshmarin, Dmitry;Almutawa, Ahmad T.;Capolino, Filippo
我们提出了一种基于异常简并点（EPDs）的耦合传输线（CTLs）色散工程新范例。我们还提出了由四个Floquet-Bloch本征模合并成一个简并本征模的四阶EPDs的理论；呈现与环境保护署相关的独特波传播特性；建立一个优点图（FOM）来评估四阶epd在CTLs中的容差和损失的实际发生情况；并通过微波频率下微带CTLs的色散和透射测量，首次实验验证了第四EPD（简并带边缘）的存在。此外，我们报告说，基于实验观察和开发的FOM，即使存在制造公差和耗散损耗，在辐射（泄漏能量）的结构中仍然可以观察到EPD特征。我们研究了ctl中的“增益和损失平衡”机制，作为在存在辐射和/或耗散损失的情况下恢复EPD的一种手段，而不必诉诸于奇偶时间（PT）对称机制。多功能EPD概念在高强度和高能效振荡器、空间功率合成器或低阈值振荡器等应用中很有前景，并为提高大型相干源的性能开辟了新的领域。
We present a novel paradigm for dispersion engineering in coupled transmission lines (CTLs) based on exceptional points of degeneracy (EPDs). We also develop a theory for fourth-order EPDs consisting of four Floquet-Bloch eigenmodes coalescing into one degenerate eigenmode; present unique wave propagation properties associated with the EPD; develop a figure of merit (FOM) to assess the practical occurrence of the fourth-order EPDs in CTLs with tolerances and losses; and experimentally verify for the first time the existence of a fourth EPD (the degenerate band edge), through dispersion and transmission measurements in microstrip-based CTLs at microwave frequencies. In addition, we report that based on experimental observation and the developed FOM, the EPD features are still observable in structures that radiate (leak energy away), even in the presence of fabrication tolerances and dissipative losses. We investigate the “gain and loss balance” regime in CTLs as a means of recovering an EPD in the presence of radiation and/or dissipative losses, without necessarily resorting to parity-time (PT)-symmetry regimes. The versatile EPD concept is promising in applications such as high-intensity and power-efficiency oscillators, spatial power combiners, or low-threshold oscillators and opens new frontiers for boosting the performance of large coherent sources.
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影响因子：
5.7
作者：
G. Mumcu;K. Sertel;J. Volakis
通讯作者：
G. Mumcu;K. Sertel;J. Volakis
简并带边耦合谐振器光波导中的巨谐振和反常品质因数缩放
影响因子：
4.7
作者：
M. Y. Nada;M. Othman;O. Boyraz;F. Capolino
通讯作者：
F. Capolino
简并与电子束相互作用的周期性多模态慢波结构的理论和新放大机制
影响因子：
1.5
作者：
M. Othman;V. A. Tamma;F. Capolino
通讯作者：
F. Capolino
耦合传输线的简并点和分支点——线性代数和分岔理论的视角
影响因子：
5.7
作者：
G. Hanson;A. Yakovlev;M. Othman;F. Capolino
通讯作者：
F. Capolino
DOI：
10.1109/tmtt.2016.2518160
发表时间：
2016-02
影响因子：
4.3
作者：
V. A. Tamma;A. Figotin;F. Capolino
通讯作者：
V. A. Tamma;A. Figotin;F. Capolino