Ion Trap Electrode Routing for Low Magnetic Field Noise

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Solution Overview

Problem

Existing ion trap devices experience significant magnetic field noise due to the layout of signal and return lines, which affects the precise control of ion movement and state in quantum computing environments.

Innovation Solution

The electrode arrangements in the ion trap device are designed with signal and return line portions running in close proximity to each other, with the return line width no greater than 10 times the signal line width, and opposite current directions to minimize magnetic field interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If signal and return lines are routed separately with conventional layout, then ease of manufacture is improved, but magnetic field noise increases

Engineering Contradiction:
Improveease of manufactureVSAvoidmagnetic field noise
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The signal line and return line are merged into a differential pair configuration where they run parallel and adjacent to each other throughout the substrate. This merging allows the magnetic fields generated by the two lines to cancel each other out, significantly reducing magnetic field noise while maintaining ease of manufacture through standard PCB differential pair routing techniques

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention converts the potentially harmful magnetic field interference into a beneficial effect by deliberately routing the signal and return lines in close proximity with opposite current directions. The magnetic fields that would normally be harmful are now made to cancel each other, transforming the problem of magnetic interference into a solution that actively reduces noise

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

2Reliability

If return line width is increased to reduce impedance, then electrical stability is improved, but magnetic field interference increases

Engineering Contradiction:
Improveelectrical stabilityVSAvoidmagnetic field interference
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention optimizes the width parameters of both signal and return lines within specific ranges (signal line: 2-10 mils, return line: 4-20 mils) to achieve the desired impedance matching while minimizing magnetic field interference. By carefully adjusting these dimensional parameters, the design achieves electrical stability without excessive line widths that would generate harmful magnetic fields

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The return line is designed with non-uniform width along its length, with wider sections positioned away from sensitive trapped ion regions and narrower sections closer to the ions. This local variation in width allows the return line to provide adequate current return path for electrical stability while minimizing magnetic field exposure in critical areas

Inventive Principle:
Principle #3Local quality

3Area of stationary object

If signal lines are routed closer to trapped ions for compact design, then device area is reduced, but magnetic field noise increases

Engineering Contradiction:
Improvedevice areaVSAvoidmagnetic field noise
Core Design Contradiction:
Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

By merging the signal and return lines into a tight differential pair configuration, the invention achieves compact routing that can be placed close to trapped ions without significantly increasing magnetic field noise. The differential configuration ensures that magnetic fields cancel even at close distances, enabling compact device design while maintaining low noise levels

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention utilizes the vertical dimension by routing signal and return lines on adjacent layers of the PCB substrate, separated by a controlled dielectric thickness. This three-dimensional arrangement allows compact positioning near trapped ions while maintaining adequate separation between the lines themselves, reducing magnetic field interference through spatial distribution in multiple dimensions

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

This design significantly reduces magnetic field noise around trapped ions, enhancing the precision and control of ion movement and state in quantum computing operations.

Implementation Method 1

electrodes are controlled to provide an intended electromagnetic field (EM-field)... accurate control of the E-fields created by the electrodes... reduce any noise or other undesired fluctuations of the EM-field experienced by the ion(s), particularly the magnetic component

Methodology Applied
Scientific EffectElectromagnetic field: Electromagnetic Induction

Implementation Method 2

a capacitance arrangement connected between the electrode and the return line portion

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP4632633A1An ion trap device
Publication Date: 2025.10.15 INFINEON TECH AUSTRIA AG
  • EP4632633A1 patent drawingFigure 1~2
  • EP4632633A1 patent drawingFigure 3~4
  • EP4632633A1 patent drawingFigure 5

AI summary

An ion trap device in which a return line portion (230) and one or more signal line portions (220) , for driving an electrode (210) of the ion trap device, are configured to run alongside one another in close proximity for a majority of the length of the return line portion.