Eliminating Reciprocity in Radiating and Scattering Systems

Physical Sciences : Electrical

Available for licensing


  • Andrea Alu, Ph.D. , Electrical and Computer Engineering
  • Yakir Hadad , University of Texas at Austin
  • Jason Soric , Electrical and Computer Engineering

Background/unmet need

Time-reversal symmetries and reciprocity impose stringent constraints on emission and radiation. Antennas, from radio-frequencies to optics, are bound to transmit and receive data equally well from the same direction. Recently, it has been shown that the limitations imposed by reciprocity can be violated by using magnetic or non-linear materials. However, both of these methods are largely impractical due to their own associated constraints. 

Invention Description

A team of researchers at UT Austin has proposed a space-time modulation scheme in order to violate reciprocity in radiation and scattering scenarios. The team has shown theoretically and experimentally that by applying this scheme, reciprocity can be violated with a linear system that is made of readily available, simple, compact, and unexpansive electronic components compared to the bulky duplexers and non-reciprocal magnet-based phase shifters that are being used today. As such, this invention provides a remarkably simple and cost-effective way to overcome the stringent limitations of radiating systems and opens up new possibilities in a variety of industries. 


    Means to significantly alter a structures absorptivity and emissivity without the use of bulky duplexers or rare-earth materials. 


  • Provides a potential solution to a wide range of problems in telecommunication, aerospace, and energy harvesting.
  • A remarkably simple and compact scheme to overcome stringent limitations of radiating systems

Market potential/applications

- In telecommunication: antennas in highly dense environments are prone to receive echoes of their own transmission or noise; therefore by having an antenna that can transmit without receiving this issue will be resolved.
- In aerospace and military industry: sensors that behave as one-way mirrors may have a potential key role in future applications.
- In energy harvesting: Kirchhoffs law states that in reciprocal system at thermodynamic equilibrium, emission and absorption are equal, implying inherent loss in thermophotovoltaics. Non-reciprocal absorbers that can absorb without emitting will solve this issue.

Development Stage

Proof of concept

IP Status