Experimental realization of an active non-reciprocal metamaterial using an eigen-structure assignment control...

Area of Science:

• Acoustics
• Metamaterials
• Control Theory

Background:

• Controlling acoustic wave propagation is crucial for various applications.
• Existing methods for achieving non-reciprocity often involve nonlinearities, complex components, or spatiotemporal modulation.
• A need exists for linear, controllable methods to manage acoustic wave directionality.

Purpose of the Study:

• To present a novel class of active non-reciprocal metamaterials (ANMMs).
• To demonstrate a method for controlling acoustic wave flow in a one-dimensional duct.
• To achieve desirable non-reciprocal behavior through eigen-structure assignment.

Main Methods:

• Designing a controller through simultaneous allocation of eigenvalues and eigenvectors.
• Assigning the entire eigen-structure of the closed-loop system.
• Focusing on adjusting eigenvectors for spatial wave control and redistribution.
• Maintaining linear system behavior throughout the process.

Main Results:

• Successful demonstration of basic features and control characteristics of ANMMs.
• Experimental validation of the proposed method for achieving non-reciprocal acoustic wave behavior.
• Achieved spatial control and redistribution of wave propagation along an acoustic duct.

Conclusions:

• The proposed eigen-structure assignment method effectively controls acoustic wave propagation.
• Active non-reciprocal metamaterials offer a new pathway for linear acoustic wave manipulation.
• The developed strategies can be extended to two-dimensional acoustic systems.