Technology - Magnet/Piezo-free Metamaterial with Temporally Varying Elastic Properties

Magnet/Piezo-free Metamaterial with Temporally Varying Elastic Properties

A metamaterial which allows acoustic waves to pass in one direction only.


Diodes allow electrical current to pass in one direction only which makes them fundamental to modern electronics.  Unfortunately, an equivalent device does not exist for electromagnetic and acoustic waves.  These waves are reciprocal, traveling equally well in all directions.  However, if a diode-like device existed for these waves it could absorb or re-direct them protecting vulnerable structures, minimizing vibrations, or reducing signal interference.   M.A. Attarzadeh, J. Callanan, and M. Nouh, “Experimental Observation of Nonreciprocal Waves in a Resonant Metamaterial Beam”, Phys. Rev. Applied 13, 021001 – Published 14 February 2020

Technology Overview:

This metamaterial, developed by University at Buffalo researchers, breaks wave reciprocity allowing waves to pass in one direction only.  The material consists of cantilevered resonators attached to a central host beam.  The resonators consist of a flat beam attached at the right angle to the main beam shifted slightly relative to each other.  The orientation of the resonator arms is spun in unison by embedded motors.  The spinning alters the central beam's stiffness in a manner to create a dynamic space-time varying metamaterial capable of breaking wave reciprocity.  The net effect is waves traveling differently through the beam depending on direction.


  • Eliminates back scatter.
  • Requires no piezoelectric or magnetic components.
  • Tunable.
  • Does not rely on response to external stimulus.


  • Medical imaging.
  • Sound mitigation.
  • Vibration control.
  • Telecommunications.
  • Defence.
  • Sensor-actuator protection.
  • Sonar and radar.

Intellectual Property Summary:

Non-provisional patent application 17/507,798 filed 10/21/21.

Licensing Status:

Available for licensing or collaboration.

Additional Information:

Patent Information: