Sasmal Aritra, Geib Nathan, Popa Bogdan-Ioan, Grosh Karl
Department of Mechanical Engineering, University of Michigan.
Department of Mechanical Engineering, University of Michigan and Department of Biomedical Engineering, University of Michigan.
New J Phys. 2020 Jun;22(6). doi: 10.1088/1367-2630/ab8aad.
The ability to create linear systems that manifest broadband nonreciprocal wave propagation would provide for exquisite control over acoustic signals for electronic filtering in communication and noise control. Acoustic nonreciprocity has predominately been achieved by approaches that introduce nonlinear interaction, mean-flow biasing, smart skins, and spatio-temporal parametric modulation into the system. Each approach suffers from at least one of the following drawbacks: the introduction of modulation tones, narrow band filtering, and the interruption of mean flow in fluid acoustics. We now show that an acoustic media that is non-local and active provides a new means to break reciprocity in a linear fashion without these deleterious effects. We realize this media using a distributed network of interlaced subwavelength sensor-actuator pairs with unidirectional signal transport. We exploit this new design space to create a stable metamaterial with non-even dispersion relations and electronically tunable nonreciprocal behavior over a broad range of frequencies.
能够创建表现出宽带非互易波传播的线性系统，将为通信和噪声控制中的电子滤波提供对声信号的精确控制。声学非互易性主要是通过将非线性相互作用、平均流偏置、智能表皮和时空参数调制引入系统的方法来实现的。每种方法都至少存在以下缺点之一：引入调制音、窄带滤波以及流体声学中平均流的中断。我们现在表明，一种非局部且有源的声学介质提供了一种以线性方式打破互易性而无这些有害影响的新方法。我们使用具有单向信号传输的交错亚波长传感器 - 致动器对的分布式网络来实现这种介质。我们利用这个新的设计空间来创建一种具有非均匀色散关系且在很宽频率范围内具有电子可调非互易行为的稳定超材料。
