# US 2023/0067066 A1 · Connecting Electrical Circuitry in a Quantum Computing System

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- Number: US 2023/0067066 A1
- Document ID: US20230067066A1
- Status: Published application
- Kind: A1
- Application number: 17/723,147
- Filed: 2022-04-18
- Published: 2023-03-02
- Earliest claimed: 2017-05-16
- Assignees: Rigetti & Co, LLC
- Applicants: Rigetti & Co, LLC
- Inventors: Tristan Ossama El Bouayadi; Damon Stuart Russell; Jean-Philip Paquette; Saniya Vilas Deshpande
- Web page: https://patentgrep.com/patent/US20230067066A1

## CPC

- H01P 3/08: Microstrips; Strip lines
- H05K 1/0221: {Coaxially shielded signal lines comprising a continuous shielding layer partially or wholly surrounding the signal lines}
- G06N 10/40: Physical realisations or architectures of quantum processors or components for manipulating qubits, e.g. qubit coupling or qubit control
- H01P 1/30: for compensation of, or protection against, temperature or moisture effects {; for improving power handling capability (H01P1/04, H01P1/08 take precedence)}
- H05K 1/0203: {Cooling of mounted components (H05K1/0272 takes precedence)}
- H05K 1/0243: {Printed circuits associated with mounted high frequency components}
- H05K 1/0245: {Lay-out of balanced signal pairs, e.g. differential lines or twisted lines}
- H05K 1/147: {at least one of the printed circuits being bent or folded, e.g. by using a flexible printed circuit (H05K1/148 takes precedence)}
- H05K 1/189: characterised by the use of flexible or folded printed circuits
- H05K 3/365: {by abutting, i.e. without alloying process}
- H05K 7/20372: {Cryogenic cooling; Nitrogen liquid cooling}
- H01B 7/04: Flexible cables, conductors, or cords, e.g. trailing cables
- H01R 12/79: connecting to rigid printed circuits or like structures
- H05K 1/0204: {using means for thermal conduction connection in the thickness direction of the substrate (H05K1/0207 takes precedence)}
- H05K 1/0225: {Single or multiple openings in a shielding, ground or power plane (H05K1/0227 takes precedence)}
- H05K 1/0233: {Filters, inductors or a magnetic substance}
- H05K 1/0234: {Resistors or by disposing resistive or lossy substances in or near power planes (H05K1/0246 takes precedence)}
- H05K 1/025: {Impedance arrangements, e.g. impedance matching, reduction of parasitic impedance (H05K1/024 and H05K1/0243 take precedence; for semiconductor devices H10W44/20)}
- H05K 3/0061: {onto a metallic substrate, e.g. a heat sink (heat sinks for electric apparatus H05K7/20)}
- H05K 2201/0154: Polyimide
- H05K 2201/05: Flexible printed circuits [FPCs]
- H05K 2201/0715: provided by an outer layer of PCB
- H05K 2201/09809: Coaxial layout
- H05K 2201/1006: Non-printed filter
- H05K 2201/10409: Screws
- H01P: WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE (operating at optical frequencies G02B)
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- G06N: COMPUTING ARRANGEMENTS BASED ON SPECIFIC COMPUTATIONAL MODELS
- H01B: CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES (selection for magnetic properties H01F1/00; waveguides H01P {; printed circuits H05K})
- H01R: ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS

## Abstract

In some aspects, a flexible cable may comprise: a flexible strip with first and second parallel surfaces and first and second ends, said flexible strip being electrically insulating; a metal stripline within said flexible strip; first and second metallic grounding planes on said first and second surfaces, respectively; and a first circuit board mechanically attached to at least one of said first end of said flexible strip and said first and second metallic grounding planes at said first end, said first circuit board being mechanically stiff, said metal stripline being electrically connected to electrical circuitry on said first circuit board.

## Claims

### Claim 1

A flexible cable comprising:
a flexible strip with first and second parallel surfaces and first and second ends, the flexible strip being electrically insulating;
a first metal stripline within the flexible strip;
first and second metallic grounding planes on the first and second parallel surfaces, respectively; and
a mechanical stiffener material attached to at least an end portion of one of the first and second ends of the flexible cable to at least one of the first and second metallic grounding planes.

### Claim 2 (depends on 1)

The flexible cable of claim 1, wherein the metal stripline is formed of superconducting material.

### Claim 3 (depends on 2)

The flexible cable of claim 2, wherein the metal stripline comprises a type-one superconducting metal.

### Claim 4 (depends on 2)

The flexible cable of claim 2, wherein the metal stripline comprises a type-two superconducting metal.

### Claim at position 5

5-7. (canceled)

### Claim 8 (depends on 1)

The flexible cable of claim 1, further comprising a second metal stripline parallel to the metal stripline along the length of the flexible strip.

### Claim 9 (depends on 1)

The flexible cable of claim 1, further comprising a multiplicity of metallic vias through the flexible strip connecting the first and second metallic grounding planes, the metallic vias being arrayed on both sides of the metal stripline, wherein the metal stripline is within an electromagnetically shielded volume defined by the multiplicity of metallic vias and the first and second grounding planes.

### Claim 10 (depends on 9)

The flexible cable of claim 9, further comprising a second metal stripline parallel to the metal stripline along the length of the flexible strip, the metallic vias being arrayed on both sides of and between the metal stripline and the second metal stripline, wherein the metal stripline and the second metal stripline are within an electromagnetically shielded volume defined by the multiplicity of metallic vias and the first and second grounding planes.

### Claim 11

(canceled)

### Claim 12 (depends on 1)

The flexible cable of claim 1, wherein the flexible strip comprises polyimide.

### Claim 13 (depends on 1)

The flexible cable of claim 1, wherein the flexible strip comprises KAPTON®.

### Claim 14 (depends on 9)

The flexible cable of claim 9, wherein the electromagnetic shielding is over at least a range comprising microwave frequencies.

### Claim at position 13

15-16. (canceled)

### Claim 17 (depends on 1)

The flexible cable of claim 1, wherein the flexible strip comprises a composite material, the composite material comprising an insulating material and metallic particles for absorption of high-frequency electromagnetic waves.

### Claim 18 (depends on 1)

The flexible cable of claim 1, further comprising:
a second flexible strip on the second metallic grounding plane, a third metallic grounding plane on the surface of the second flexible strip wherein the second and third metallic grounding planes are parallel, the flexible strip being electrically insulating; and
a second layer metal stripline within the second flexible strip;
wherein the second layer metal stripline is electrically connected to electrical circuitry on the first circuit board.

### Claim 19 (depends on 9)

The flexible cable of claim 9, further comprising:
a second flexible strip on the second metallic grounding plane, a third metallic grounding plane on the surface of the second flexible strip wherein the second and third metallic grounding planes are parallel, the flexible strip being electrically insulating;
a second multiplicity of metallic vias through the flexible strip connecting the third and second metallic grounding planes, the metallic vias being arrayed on both sides of the second layer metal stripline, wherein the second layer metal stripline is within an electromagnetically shielded volume defined by the second multiplicity of metallic vias and the third and second grounding planes; and
a second layer metal stripline within the second flexible strip;
wherein the second layer metal stripline is electrically connected to electrical circuitry on the first circuit board.

### Claim 20

A cryogenic system comprising:
a plurality of isothermal plates; and
at least one flexible cable comprising:
a flexible strip with first and second parallel surfaces and first and second ends, the flexible strip being electrically insulating;
a first metal stripline within the flexible strip;
first and second metallic grounding planes on the first and second parallel surfaces, respectively; and
a mechanical stiffener material attached to at least an end portion of one of the first and second ends of the flexible cable to at least one of the first and second metallic grounding planes; and
a quantum processing unit electrically connected to the at least one flexible cable at the first end, the quantum processing unit comprising superconducting circuits, wherein the cryogenic system is configured for the flexible cable to carry one or more signals to the quantum processing unit,
and an electrical connector providing electrical connection of the at least one flexible cable and the quantum processing unit.

### Claim 21

(canceled)

### Claim 22 (depends on 20)

The cryogenic system of claim 20, wherein the quantum processing unit comprises greater than or equal to fifty quantum bits.

### Claim 23 (depends on 20)

The cryogenic system of claim 20, wherein the quantum processing unit comprises greater than or equal to one hundred quantum bits.

### Claim 24

(canceled)

### Claim 25 (depends on 21)

The cryogenic system of claim 21, wherein the at least one flexible cable passes through all of the plurality of isothermal plates, including the mixing plate, except for a room temperature plate, the second end being mechanically and thermally connected to the room temperature plate.

### Claim at position 23

26-38. (canceled)

### Claim 39 (depends on 20)

A cryogenic system of claim 20, wherein the electrical connector is a compliant joint.

### Claim at position 25

40-41. (canceled)

### Claim 42 (depends on 1)

The flexible cable of claim 1, wherein the mechanical stiffener material comprises polyimide.

### Claim 43 (depends on 1)

The flexible cable of claim 1, wherein the mechanical stiffener material comprises polyimide dielectric.

### Claim 44 (depends on 1)

The flexible cable of claim 1, wherein the mechanical stiffener material comprises a fiberglass composite.