Magnetless Microwave Circulators Based on Spatiotemporally Modulated Rings of Coupled Resonators
Magnetless Microwave Circulators Based on Spatiotemporally Modulated Rings of Coupled Resonators
复制标题
DOI：
10.1109/tmtt.2015.2511737
复制
发表时间：
2016-02-01
影响因子：
4.3
通讯作者：
Alu, Andrea
中科院分区：
文献类型：
--
作者：
Estep, Nicholas Aaron;Sounas, Dimitrios L.;Alu, Andrea
不可逆元件在电子和光学系统中无处不在。迄今为止，使用磁光材料已成为实现非互易性的主流方法。然而，基于磁性的器件存在一些缺点，例如需要笨重的偏置器件以及它们与半导体技术的不兼容，这使得它们的集成具有挑战性。最近，由于射频信号赋予结构有效的自旋，在时空调制耦合谐振器网络中证明了强无磁非互易性。这些结构可以轻松集成，并且与任何参数设备一样，它们可能表现出良好的功率和噪声性能。在这里，我们为此类设备开发了一种分析理论，可以确定设计具有最佳特性的条件，并提出了两种基于集总和分布式元件电路的设计，分别适用于甚高频和无线通信频段的应用。环行器在合理的调制要求内表现出高隔离度和低插入损耗。此外，它们可以通过远低于输入频率的调制频率来实现，从而显着简化设计。提供了集总元件设计的测量结果，并显示出与理论和全波仿真的良好一致性。还研究了所提出设计的非线性特性，并探索了通过增加变容二极管的静态偏置或使用先进的变容二极管拓扑来减少非线性失真的可能方法。
Nonreciprocal components are ubiquitous in electronic and optical systems. To date, the use of magneto-optical materials has been the prevailing method to achieve non-reciprocity. However, magnetic-based devices are accompanied by several drawbacks, such as the requirement of bulky biasing devices and their incompatibility with semiconductor technology, which make their integration challenging. Recently, strong magnetless nonreciprocity was demonstrated in spatiotemporally modulated coupled-resonator networks as a result of an effective spin imparted to the structure by an RF signal. These structures can be easily integrated, and they potentially exhibit good power and noise performance, as any parametric device. Here, we develop an analytical theory for such devices, which allows determining the conditions for designing them with optimum characteristics, and present two designs based on lumped-and distributed-element circuits for applications at the very high-frequency and wireless-communications bands, respectively. The circulators exhibit large isolation and low insertion loss within reasonable modulation requirements. Furthermore, they can be realized with a modulation frequency substantially lower than the input frequency, significantly simplifying the design. Measurements for the lumped-element design are provided and show good agreement with theory and full-wave simulations. The nonlinear characteristics of the presented designs are also studied, and possible ways to reduce nonlinear distortion by increasing the static bias of the varactors or using advanced varactor topologies are explored.