US 4,227,096 A · Microwave integrated circuit for Josephson voltage standards

Microwave integrated circuit for Josephson voltage standards

OwnerRobert A. Administrator of the National Aeronautics and Space Administration, with respect to an invention of Frosch, Louis B. Holdeman +2inventors

InventorsRobert A. Administrator of the National Aeronautics and Space Administration, with respect to an invention of Frosch, Louis B. Holdeman, Jaan Toots, Chu-Cheng Chang

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Abstract

A microwave integrated circuit, comprised of one or more Josephson junctions and short sections of microstrip or stripline transmission line, is fabricated from thin layers of superconducting metal on a dielectric substrate. The short sections of transmission line are combined to form the elements of the circuit, and particularly, two microwave resonators. The Josephson junctions are located between the resonators, and the impedance of the Josephson junctions forms part of the circuitry that couples the two resonators. The microwave integrated circuit has an application in Josephson voltage standards. In this application, the device is asymmetrically driven at a selected frequency (approximately equal to the resonance frequency of the resonators), and a D.C. bias is applied to the junction. By observing the current-voltage characteristic of the junction, a precise voltage, proportional to the frequency of the microwave drive signal, is obtained.

Claims6

Dependent claims

A Josephson junction type voltage standard comprising:

first and second electrical resonators tuned to resonate at a selected, like, frequency;
a Josephson junction connected electrically between said resonators;
coupling means for coupling a signal of said selected frequency to at least one of said resonators;
a D.C. series circuit comprising a low-pass filter, a variable potential D.C. junction bias source, and said resonators for applying a selectable bias to said Josephson junction;
and
means coupled to said series circuit for detecting the current-voltage characteristic of said Josephson junction, whereby a precise voltage related to said frequency may be determined.

3 more elements

Dependencies are inferred from the claim text.