Non-reciprocal electronics based on temporal modulation


In general, reciprocity requires that signals travel in the same manner in both forward and reverse directions. It governs the behaviour of the majority of electronic circuits and components, imposing severe restrictions on how they operate. Components that violate reciprocity, such as gyrators, isolators and circulators, are, however, of use in many different electronic applications. Non-reciprocal electronic components have typically been implemented using ferrites, but such magnetic materials cannot be integrated in modern semiconductor fabrication processes and magnetic non-reciprocal components remain bulky and expensive. Creating non-reciprocal components without the use of magnetic materials has a long history, but has recently been reinvigorated due to advancements in semiconductor technology. Here we review the development of non-reciprocal devices and the development of non-magnetic non-reciprocal electronics, focusing on devices based on temporal modulation, which arguably exhibit the greatest potential. We consider approaches based on temporal modulation of permittivity and conductivity, as well as hybrid acoustic–electronic components, which have applications including high-power transmitters for communications, simultaneous transmit and receive radars, and full-duplex wireless radios. We also explore superconducting non-reciprocal components based on temporal modulation of permeability for potential applications in quantum computing and consider the key future challenges in the field.

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Fig. 1: Non-reciprocity based on active transistors or nonlinearity.
Fig. 2: Non-reciprocity based on temporal modulation of permittivity or capacitance.
Fig. 3: Non-reciprocity through temporal conductivity modulation on semiconductor substrates.
Fig. 4: Non-reciprocity in hybrid electro-acoustic devices.
Fig. 5: Non-reciprocity through time-variance at cryogenic temperatures targeting quantum computing applications.


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This work was supported by the National Science Foundation, the Air Force Office of Scientific Research, and the Defense Advanced Research Projects Agency. We wish to thank T. Olsson and T. Hancock for useful feedback and comments.

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A.N., N.R. and H.K. performed literature review and wrote the manuscript. H.K. directed and supervised the project.

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Correspondence to Harish Krishnaswamy.

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Nagulu, A., Reiskarimian, N. & Krishnaswamy, H. Non-reciprocal electronics based on temporal modulation. Nat Electron 3, 241–250 (2020).

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