Waveguide Rotary Coupling for High-Bandwidth CT Scanner Data Links

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Solution Overview

Problem

Existing rotary joints for CT scanners face limitations in high-speed data transfer due to small relative bandwidth and the need for narrow radial slots, which restricts the efficiency and bandwidth of microwave signal transmission.

Innovation Solution

A rotary joint design featuring coaxially arranged first and second rings with conductive material, a circular gap, and rotatable antennas, allowing for efficient microwave signal transfer through optimized beam angles and reflective materials to minimize signal distortion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a waveguide is used for transmitting signals, then signal transmission is achieved, but the relative bandwidth is small which limits the usable data rate

Engineering Contradiction:
Improvedata rateVSAvoidbandwidth
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent replaces the traditional waveguide structure with a free-space optical communication system using lasers and photodetectors. This substitution eliminates the bandwidth limitations of waveguides by using optical frequencies, enabling much higher data rates while maintaining signal transmission capability through the rotary joint.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the fundamental transmission parameter from microwave frequencies in waveguides to optical frequencies using lasers. This parameter change increases the available bandwidth by several orders of magnitude, directly resolving the contradiction between achieving signal transmission and maintaining high bandwidth for high data rates.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a radial slot is made narrow to avoid waveguide degradation, then waveguide integrity is maintained, but the transmission antenna must be a small pin which limits bandwidth and efficiency

Engineering Contradiction:
Improvewaveguide integrityVSAvoidtransmission efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent replaces the waveguide-based microwave transmission system with a free-space optical system. This eliminates the need for radial slots and pin antennas entirely, as optical signals are transmitted through air space between the rotating and stationary components, thereby maintaining waveguide integrity while dramatically improving transmission efficiency through the use of optical detectors and lasers.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Area of stationary object

If a large diameter is used for the rotary joint to accommodate CT scanner bore, then patient accommodation is enabled, but the complexity of maintaining alignment and signal quality increases

Engineering Contradiction:
Improverotary joint diameterVSAvoidalignment maintenance
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent replaces the waveguide system with free-space optical communication. This substitution reduces alignment complexity because optical components like lasers and photodetectors can tolerate larger angular deviations compared to waveguide interfaces. The large diameter rotary joint can thus rotate through greater angles while maintaining signal quality, reducing the precision requirements for mechanical alignment.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 solution achieves improved high-speed coupling between rotatable parts, enabling higher bandwidth and reduced signal distortion, thus enhancing data transfer efficiency in CT scanners.

Implementation Method 1

The first antenna and the second antenna are configured for a microwave signal connection between them

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Implementation Method 2

The first ring and the second ring may reflect microwave signals, such that the microwave signals propagate through the ring

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP4335000B1Rotary transmission system using a waveguide
Publication Date: 2025.06.11 SCHLEIFRING GMBH
  • EP4335000B1 patent drawingFigure 1~3
  • EP4335000B1 patent drawingFigure 4~5
  • EP4335000B1 patent drawingFigure 6

AI summary

A coupler provides a high speed datalink between rotatable parts comprising a circular gap enclosing a hollow-cylindric volume and at least two antennas. The circular gap is of electrically conductive material and includes a first ring, a second ring rotatable against the first ring, and two sidewalls on both sides of the rings. A first antenna is mechanically coupled to the first ring and a second antenna is mechanically coupled to the second ring. The antennas are configured for a microwave signal connection between them based on multiple reflections at the rings.