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A resonant metamaterial clock distribution network for superconducting logic


Clock distribution is central to digital technology and influences circuit performance, interconnect overhead and efficiency. However, ensuring reliable clock distribution across large digital systems with low skew and jitter—and in the presence of device variations and thermal noise—is a design challenge. Here we report a superconducting metamaterial resonant clock network that can provide energy-efficient power delivery to large superconducting digital systems. The resonant clock network is based on a metamaterial design with an infinite-wavelength zeroth-order resonance mode and utilizes the ultralow Joule loss of superconductors at microwave frequencies. With this approach, we perform S-parameter measurements for a 10 GHz design and validate a digital reciprocal quantum logic circuit with 48,000 junctions operating at 3.5 GHz. The network supports uniform power distribution with less than 1 dB variation across a 3 × 3 mm2 active chip area and around 30% power efficiency. Static power dissipation is 28 μW, which is similar to that of active devices.

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Fig. 1: Conceptual design of the resonant clock network.
Fig. 2: Microwave characterization of the resonator at 4.2 K powering RQL circuits at ~10 GHz clock frequency and with 4.5 mm2 active area.
Fig. 3: Functional characterization of resonator uniformity at 4.2 K using a shift-register test circuit covering 3 × 3 mm2 active area of the chip.
Fig. 4: A DynaZOR clock network fills the active area on a 5 mm chip with spines running vertically along the left and right edges and ribs running horizontally between them.

Data availability

The data that support the findings of this study are available from the corresponding author upon reasonable request.


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We acknowledge the valuable conversation with O. Naaman regarding the clock network design. H. Dai and J. Egan assisted with the physical design of the clock network and functional circuits. J. Goodman and M. Lateef assisted with the microwave measurement. D. Harvey assisted with the circuit design. This research is based on the work supported in part by the ODNI, IARPA, via ARO, contract no. W911NF-14-C-0116. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of the ODNI, IARPA, or the US Government.

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Authors and Affiliations



J.A.S. and V.V.T. conceived the idea, performed the analysis and wrote the manuscript. M.E.N. performed the electrical and physical design and modelling, as well as conceived several design improvements. A.C.B. and N.B. performed the measurements and analysed the data. A.Y.H. and Q.P.H. initiated and supervised the work.

Corresponding author

Correspondence to Joshua A. Strong.

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Competing interests

All authors are or have been employed by Northrop Grumman Corp., which holds several patents relating to work discussed herein. See U.S. Patents 10,591,952; 10,884,450; 10,474,183; 10,461,867; 10,133,299; 9,722,589.

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Nature Electronics thanks Nobuyuki Yoshikawa and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Strong, J.A., Talanov, V.V., Nielsen, M.E. et al. A resonant metamaterial clock distribution network for superconducting logic. Nat Electron 5, 171–177 (2022).

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