Rigid PCB Signal Routing for Low-Noise Cryogenic Transmission

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Solution Overview

Problem

Mechanical vibrations in cryostats, particularly caused by pulse tube refrigerators, induce significant electrical noise on signal lines in low-temperature environments, especially at low frequencies and short integration times, affecting measurements and control operations in quantum computing and sensing.

Innovation Solution

Rout low-frequency signal lines in a dilution refrigerator using rigid printed circuit boards (PCBs) with tight spacing and avoid flexible cables in high magnetic field regions, minimizing inductive and triboelectric noise by reducing relative movement and loop area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If flexible cables are used for signal lines in cryostats, then ease of connection and routing is improved, but mechanical vibrations induce significant electrical noise especially at low frequencies

Engineering Contradiction:

Improveease of connectionVSAvoidelectrical noise

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent replaces flexible mechanical cable connections with rigid printed circuit board (PCB) traces. The PCB provides electrical connectivity without the mechanical flexibility that allows vibration-induced noise. The rigid structure eliminates relative movement between signal lines and the cryostat walls, thereby preventing triboelectric noise and reducing inductive pickup from vibrations.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses thin flexible printed circuit boards (FPCBs) as an intermediate solution. These thin films maintain electrical connectivity while being thin enough to minimize loop area and vibration-induced noise, combining the flexibility needed for connection with the rigidity needed to reduce noise.

Inventive Principle:

Principle #30Flexible shells and thin films

2Ease of manufacture

If signal lines are routed with larger spacing, then ease of manufacturing and routing is improved, but loop area increases leading to higher inductive pickup from magnetic field vibrations

Engineering Contradiction:

Improveease of routingVSAvoidinductive pickup

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent applies different spacing strategies in different regions of the PCB. In regions where signal lines pass through or near magnetic field regions, the spacing is minimized to reduce loop area and inductive pickup. In regions away from magnetic fields, standard spacing is used for ease of manufacturing and routing. This local optimization resolves the contradiction between manufacturing ease and noise reduction.

Inventive Principle:

Principle #3Local quality

3Measurement precision

If measurement integration time is increased, then signal-to-noise ratio is improved, but measurement speed decreases affecting productivity

Engineering Contradiction:

Improvesignal-to-noise ratioVSAvoidmeasurement speed

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent converts the harmful effect of mechanical vibrations into a benefit by using rigid PCB structures that eliminate the source of vibration-induced noise. By eliminating the noise at its source through rigid connections, measurements can be performed quickly with short integration times while maintaining high signal-to-noise ratios, thus improving both measurement precision and productivity simultaneously.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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

Reduces vibration-induced electrical noise, enabling faster and more accurate measurements by minimizing inductive pickup and triboelectric noise, thus supporting scalable quantum device operations.

Implementation Method 1

minimizing inductive and triboelectric noise by reducing relative movement

Methodology Applied

Scientific EffectTriboelectric effect: Triboelectric Effect

Implementation Method 2

minimizing inductive pickup

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS20260079201A1Systems, components and mechanisms to support electrical signal transmission in low temperature environments

Publication Date: 2026.03.19 MICROSOFT TECHNOLOGY LICENSING LLC

AI summary

Electrical communication between a sample (such as a quantum chip, semiconductor sample etc.) in a low temperature environment and an external device is affected via signal lines printed on rigid printed circuit board (PCB) located within a region of the low temperature environment (e.g., a non-uniform magnetic field region). One example application is performing a measurement of an electrical property of the sample at a low signal frequency with a short measurement integration time, although the subject matter is not limited in this respect. Another application is routing an electrical control signal to the sample.