Drum-Style Slip-Ring Modules for High-Frequency Signal Transmission

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Contact-type slip-rings face significant limitations in transmitting high-frequency signals due to waveform distortion from impedance discontinuities and energy loss, particularly at high frequencies, which existing technologies struggle to address effectively while maintaining cost-effectiveness.

Innovation Solution

A drum-style slip-ring module is constructed using printed circuit board technology with stacked electrically-conductive rings and alternating dielectric layers, incorporating a cylindrical ground plane and controlled-impedance transmission lines to minimize impedance mismatches and enhance high-frequency performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If contact-type slip-rings are used to transmit high-frequency signals, then signal transmission between rotating and stationary members is achieved, but waveform distortion occurs due to impedance discontinuities

Engineering Contradiction:
Improvesignal transmission reliabilityVSAvoidwaveform distortion
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent changes the impedance parameter throughout the slip-ring system by using controlled-impedance transmission lines with characteristic impedance Z0 matched at all interfaces. The ring structures are designed with specific impedance characteristics, and the brush contact structures are engineered to maintain consistent impedance, thereby eliminating reflections and waveform distortion while preserving signal transmission reliability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The slip-ring system is segmented into distinct impedance-controlled transmission line sections: the ring transmission lines, the brush contact structures, and the external interface transmission lines. Each segment is designed with controlled impedance characteristics, and the segmentation allows for systematic impedance matching at each interface, preventing waveform distortion while maintaining reliable signal transmission.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If traditional slip-ring structures are used, then mechanical contact for signal transmission is achieved, but severe distortion occurs due to multiple impedance-mismatched transitions

Engineering Contradiction:
Improvesignal transmission capabilityVSAvoidsignal distortion
Core Design Contradiction:
Ease of operationVSLoss of information

Solution Approach 1:

The patent transforms the traditional slip-ring structure into an impedance-controlled transmission line system by changing the electrical parameters of each component. The rings are designed with controlled impedance, the brush contacts are engineered to maintain impedance continuity, and all interfaces are matched to the same characteristic impedance, thereby enabling high-fidelity signal transmission without severe distortion.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces impedance-matched transmission line structures as intermediaries between the rotating and stationary components. These transmission lines act as mediators that bridge the gap between different electrical domains while maintaining impedance continuity, thereby preventing signal distortion and enabling reliable high-frequency transmission.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If conventional slip-ring designs are employed, then cost-effective manufacturing is achieved, but energy loss increases with frequency due to resonance and parasitic effects

Engineering Contradiction:
Improvemanufacturing cost-effectivenessVSAvoidenergy loss at high frequency
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent changes the electrical parameters of the slip-ring components to minimize parasitic effects. By designing the rings and brush contacts as controlled-impedance transmission lines with properly matched characteristics, the patent reduces parasitic inductance and capacitance, thereby minimizing energy loss due to resonance and parasitic effects while maintaining cost-effective manufacturing using conventional techniques.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If other techniques such as fiber optic or capacitive coupling are used, then high-frequency performance is improved, but system cost increases significantly

Engineering Contradiction:
Improvehigh-frequency performanceVSAvoidsystem cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs conventional, cost-effective materials and manufacturing techniques to create impedance-controlled transmission lines that achieve high-frequency performance. Instead of using expensive fiber optic or capacitive coupling systems, the patent uses affordable metallic rings and brush contacts designed with controlled impedance, thereby achieving high-frequency reliability at a fraction of the cost of alternative technologies.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 enables extended high-frequency performance up to several gigahertz with reduced distortion and energy loss, achieving a cost-effective and manufacturable design for high-frequency signal transmission.

Implementation Method 1

a plurality of alternating intermediate dielectric layers positioned between and electrically isolating the conductive rings

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Implementation Method 2

Each of the dielectric layers includes provisions for the construction of internal transmission line feed structures, including a cylindrical ground plane positioned in the centrally-located aperture, coaxial with the ring system

Methodology Applied
Scientific EffectElectromagnetic shielding: Faraday Cage

Implementation Method 3

The techniques of this invention allow for extended high-frequency performance in a drum-style slip-ring, due to the construction of impedance-controlled transmission lines throughout the structures

Methodology Applied
Scientific EffectElectrical signal transmission: Conduction (electrical)

Data Source

PatentEP2102948B1High-frequency drum-style slip-ring modules
Publication Date: 2015.12.09 MOOG INC
  • EP2102948B1 patent drawingFigure 1~4
  • EP2102948B1 patent drawingFigure 5

AI summary

A high-frequency drum-style slip-ring module (100) is used in a contact-type communication system. The module utilizes PCB construction to construct a plurality of stacked electrically-conductive rings (102) and a plurality of dielectric layers (104) electrically isolating the conductive rings. Each of the dielectric layers includes a centrally-located aperture (107). The module also includes a cylindrical ground plane (108) positioned in the centrally-located aperture. The module is configured to provide electrical connection to each of the rings at an exterior surface of the module. Each group of feed line vias can be designed as impedance-controlled transmission lines with connections to each ring group. The construction described in this invention can create slip-ring transmission line structures with bandwidth from DC to 5 GHz or higher, allowing the slip-ring to be used to transfer multi-gigabit digital data streams.