Parity-Time Symmetric Metamaterial and Metasurface for Broadband Invisible Cloaks and Other Devices

Physical Sciences : Materials and Compounds

Available for licensing


  • Andrea Alu, Ph.D. , Electrical and Computer Engineering
  • Romain Fleury , University of Texas at Austin
  • Dimitrios Sounas, Ph.D. , Wireless Networking and Communications Group

Background/unmet need

Metamaterials are artificially structured materials possessing exotic electromagnetic or acoustic properties that are not readily available in nature; for instance, a material of negative, zero, or very large index of refraction. They are associated with unusual physical phenomena with exciting potentials for applications such as negative refraction, invisible cloaking, and super-lensing. To date, their exotic properties have been typically induced by exploiting passive structural resonances, leading to an inherently narrow-band and loss-sensitive response. These drawbacks drastically limit their performance and applicability.

Invention Description

A UT Austin research group led by Prof. Andrea Alu in the Electrical and Computer Engineering Department has invented a method to induce metamaterial effects, including invisibility cloaks, planar lenses, negative refraction, and ideal invisible sensors. This innovative idea makes use of time and space symmetry to relax the bandwidth and power loss constraints typically associated with metamaterials, allowing for broadband characteristics and total resilience to losses, and opening new ways for a variety of metamaterial applications useful in military, telecommunications, analytic sensing and biomedical fields.


  • Broad bandwidth: RF to visible frequencies
  • Immunity to losses
  • Possible to apply this method to very large objects, thus useful in stationary and/or moving military objects


    This invention proposes the combination of two properly balanced thin meta-surfaces, one with loss and one with gain elements, that exploit the largely uncharted scattering properties of Parity-Time (PT) symmetric systems. In this design, the loss element will be passive, while the gain element will be actively controlled by a loss-compensation technique, achieving PT-symmetry that overcomes conventional limitations in bandwidth and loss.

Market potential/applications

Defense; telecommunications; instrument-guided surgery; analytic sensing

Development Stage

Lab/bench prototype

IP Status

  • 1 U.S. patent application filed