Superconductor circuits with active termination

Patent metadata

Field	Value
Publication number	US-9905900-B2
Application number	US-201514702044-A
Country	US
Kind code	B2
Filing date	May 1, 2015
Priority date	May 1, 2015
Publication date	Feb 27, 2018
Grant date	Feb 27, 2018

Abstract

A microwave circuit is provided that comprises a plurality of transmission lines each configured to receive and propagate a respective waveform signal of a plurality of waveform signals, and a combiner that receives and combines the plurality of waveform signals from outputs of the plurality of transmission lines into a combined output waveform signal that is output terminated by an output termination resistor. The microwave circuit further comprises a compensation signal generator that generates a compensation signal to mitigate reflections associated with the transmission of signals through the microwave circuit.

First claim

What is claimed is:

1. A microwave circuit comprising:
a plurality of transmission lines each configured to receive and propagate a respective waveform signal of a plurality of waveform signals, wherein the plurality of transmission lines operate in a superconducting circuit;
a combiner that receives and combines the plurality of waveform signals from outputs of the plurality of transmission lines into a combined output waveform signal that is output terminated by an output termination, wherein the combiner operates in the superconducting circuit; and
a compensation signal generator that generates a compensation signal to mitigate reflections associated with the transmission of signals through the microwave circuit, wherein the compensation signal is an inverted version of a sum of the total reflections in the microwave circuit.

2. The circuit of claim 1 , further comprising a waveform generator that generates a first waveform signal and a splitter for splitting the first waveform signal into the plurality of waveform signals to be provided to the plurality of transmission lines.

3. The circuit of claim 2 , wherein the splitter, the plurality of transmission lines, and the combiner form the superconducting circuit that resides in a cold space with a temperature environment that is at superconducting cryogenic temperatures and the waveform generator and the compensation generator resides outside the cold space in a room temperature environment.

4. The circuit of claim 2 , further comprising a first coaxial cable coupled between the waveform generator and the power splitter and a second coaxial cable coupled between the combiner and the compensation signal generator.

5. The circuit of claim 2 , wherein the waveform generator is an AC source that provides an AC input signal at a predetermined frequency and the compensation signal generator is an AC source that provides an AC compensation signal at the same predetermined frequency.

6. The circuit of claim 2 , wherein the waveform generator is terminated by an input termination resistor.

7. The circuit of claim 1 , wherein the plurality of transmission lines are each configured to provide waveform signals to one or more reciprocal quantum logic (RQL) circuits.

8. The circuit of claim 7 , wherein the plurality of waveform signals provide power and a clocking function to the RQL circuits.

9. The circuit of claim 7 , wherein the RQL circuits comprise a plurality of integrated RQL circuits associated with each of the plurality of transmission lines.

10. A microwave circuit comprising:
an AC source that generates an AC input signal;
a superconducting circuit that resides in a cold space that is maintained at superconducting cryogenic temperatures, the superconducting circuit comprising:
a splitter for splitting the AC input signal into a plurality of AC intermediate signals;
a plurality of transmission lines each configured to receive and propagate a respective AC intermediate signal of the plurality of AC intermediate signals;
a set of reciprocal quantum logic (RQL) circuits coupled to a transmission line for each of the plurality of transmission lines;
a combiner that receives and combines the plurality of AC intermediate signals from outputs of the plurality of transmission lines into a combined AC output signal; and
an output source terminated compensation signal generator that generates a compensation signal to mitigate reflections associated with the transmission of signals through the superconducting circuit, wherein the compensation signal is an inverted version of a sum of the total reflections in the microwave circuit.

11. The circuit of claim 10 , wherein the plurality of AC intermediate waveform signals provide power and a clocking functions to the RQL circuits.

12. The circuit of claim 10 , wherein the RQL circuits comprise a plurality of integrated RQL circuits.

13. The circuit of claim 10 , wherein the superconducting circuit further comprises a first coaxial cable coupled between the waveform generator and the power splitter and a second coaxial cable coupled between the power combiner and the second waveform generator.

14. The circuit of claim 10 , wherein the superconducting circuit resides on a printed circuit board as one or more components.

15. A method of compensating for discontinuities in a microwave circuit, the method comprising:
applying a waveform signal to a superconducting circuit; and
applying a compensation signal to the superconducting circuit to mitigate reflections associated with the transmission of signals associated with the waveform signal through the microwave circuit, wherein the compensation signal is an inverted version of a sum of the total reflections in the microwave circuit.

16. The method of claim 15 , wherein applying a waveform signal to the superconducting circuit comprises applying a waveform signal to each of a plurality of transmission lines of the superconducting circuit, combining waveform signals from outputs of the plurality of transmission lines into a combined output waveform signal; and providing the compensation signal to the combined output waveform signal to mitigate reflections associated with the transmission of signals through the microwave circuit.

17. The method of claim 15 , further comprising repeatedly measuring one or more operating parameters associated with operation of the superconducting circuit, adjusting a setting associated with the compensation signal, repeating the measuring of the one or more operating parameters, and the determining if the adjusted setting was more optimal than the previous setting until an optimal setting has been determined, and setting the compensation signal with the optimal setting for normal operation of the superconducting circuit.

18. The method of claim 17 , wherein the adjusting the setting comprises adjusting an amplitude of the compensation signal.

19. The method of claim 15 , wherein the waveform signal and the compensation signal are set at the same predetermined frequency.

Assignees

• Herr Quentin P
• Pesetski Aaron A
• Borodulin Pavel
• Northrop Grumman Systems Corp

Inventors

• Herr Quentin P
• Pesetski Aaron A
• Borodulin Pavel

Classifications

• H01P3/06 Primary

  Coaxial lines · CPC title

• H03K19/195

  using superconductive devices · CPC title

• H03K3/38 Primary

  by the use, as active elements, of superconductive devices · CPC title