Flexible Wiring Shield Layout for Dense Cryogenic Signal Routing

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Solution Overview

Problem

Current wiring solutions for quantum computing systems, such as coaxial cables, face challenges in increasing transmission line density while maintaining low cross-talk and heat load, and are costly and bulky, especially as the number of qubits increases.

Innovation Solution

Flexible wiring with electromagnetic shielding, using materials like copper, copper alloys, or superconductors, that allows for increased wire density without via holes, reduces crosstalk, and employs butt joints for connections, freeing up space and reducing fabrication costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If coaxial cables are used for wiring quantum computing systems, then signal integrity is maintained, but transmission line density is low and the system is bulky

Engineering Contradiction:
Improvesignal integrityVSAvoidtransmission line density
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The coaxial cable is segmented into separate components: the outer conductor is divided into folded regions that act as shields, while the inner conductors carry signals. This segmentation allows multiple signal traces to be packed closely together while maintaining shielding effectiveness, thereby increasing transmission line density without sacrificing signal integrity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The folded regions of the outer conductor are nested between adjacent signal traces, creating a nested structure where the shield is positioned within the space between conductors. This nesting arrangement provides effective electromagnetic shielding while maximizing the use of available space, enabling higher transmission line density compared to traditional coaxial cable configurations.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Object-affected harmful factors

If coaxial cables are used for wiring quantum computing systems, then electromagnetic shielding is provided, but fabrication cost is high

Engineering Contradiction:
Improveelectromagnetic shieldingVSAvoidfabrication cost
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The invention changes the geometric parameters of the outer conductor, transforming it from a continuous cylindrical shield into folded regions with specific dimensions and spacing. This parameter change allows the same electromagnetic shielding function to be achieved with simpler, less expensive materials and manufacturing processes, reducing fabrication cost while maintaining shielding effectiveness.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The outer conductor is implemented as thin folded regions rather than thick cylindrical shields. These thin film-like structures provide sufficient electromagnetic shielding at reduced material cost and easier manufacturability, making the overall wiring system more cost-effective while maintaining the necessary shielding properties for quantum computing applications.

Inventive Principle:
Principle #30Flexible shells and thin films

3Quantity of substance

If transmission line density is increased, then wire space is reduced, but crosstalk increases

Engineering Contradiction:
Improvetransmission line densityVSAvoidcrosstalk
Core Design Contradiction:
Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The folded regions of the outer conductor serve as intermediary shielding structures positioned between adjacent signal traces. These intermediate shields block electromagnetic fields from coupling between neighboring lines, preventing crosstalk even when transmission lines are densely packed. The folded geometry provides effective shielding while occupying minimal space, enabling high density without increasing crosstalk.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The flexible wiring solution enables a substantial increase in transmission line density with reduced crosstalk and heat load, while providing a cost-effective alternative to coaxial cables, allowing for efficient operation of quantum information processing systems at low temperatures.

Implementation Method 1

the via may be filled with a superconducting material (e.g., niobium) that allows for improved signal integrity and a reduction in crosstalk

Methodology Applied
Scientific EffectSuperconductivity: Superconductivity

Implementation Method 2

Flexible wiring substrates may be folded, e.g., in an accordion-style configuration, to provide shielding between adjacent signal traces

Methodology Applied
Scientific EffectElectromagnetic shielding: Faraday Cage

Implementation Method 3

because material that is superconducting does not exhibit a DC resistance, the via metal will not lead to resistive heating

Methodology Applied
Scientific EffectSuperconductivity: Superconductivity

Implementation Method 4

the flexible wiring utilizes material, such as copper, a copper alloy (e.g., brass), or a superconductor (e.g., NbTi), that offers a relatively low thermal conductivity and therefore low heat load

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3580701B1Flexible wiring for low temperature applications
Publication Date: 2023.12.13 GOOGLE LLC
  • EP3580701B1 patent drawingFigure 1
  • EP3580701B1 patent drawingFigure 2
  • EP3580701B1 patent drawingFigure 3

AI summary

The subject matter of the present disclosure may be embodied in devices, such as flexible wiring, that include: an elongated flexible substrate; multiple electrically conductive traces arranged in an array on a first side of the elongated flexible substrate; and an electromagnetic shielding layer on a second side of the elongated flexible substrate, the second side being opposite the first side, in which the elongated flexible substrate includes a fold region between a first electronically conductive trace and a second electrically conductive trace such that the electromagnetic shielding layer provides electromagnetic shielding between the first electronically conductive trace and the second electrically conductive trace.