MRI RF Bandpass Filter With Integrated Coil Cavity Resonator

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Solution Overview

Problem

Conventional bandpass filters for MRI instruments require high manual effort during assembly, are costly due to the need for various coils and trimmer capacitors, and are susceptible to mechanical shocks and temperature dependence.

Innovation Solution

A compact RF bandpass filter with a conductive coil former and cavity design that minimizes stray fields, featuring a high quality factor and low impedance, allowing for easy manufacturing and integration with printed circuit boards.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a high-frequency bandpass filter is constructed using a separate cavity structure, then the filter performance is improved, but the device complexity and space occupation increase

Engineering Contradiction:
Improvefilter performanceVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the high-frequency bandpass filter cavity with the coil body into a single integrated structure. The cavity is formed within the coil body itself, eliminating the need for separate cavity components and reducing overall device complexity while maintaining filter performance.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The coil body serves multiple functions: it acts as both the coil structure for MRI signal generation and as the housing for the high-frequency bandpass filter cavity. This multi-functionality reduces the number of separate components needed in the system.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If a high-frequency bandpass filter is constructed using a separate cavity structure, then the filter performance is improved, but the space occupation increases

Engineering Contradiction:
Improvefilter performanceVSAvoidspace occupation
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The cavity structure is nested within the coil body, with the filter cavity forming an internal space within the existing coil structure. This nesting approach allows the filter to be housed within the volume already occupied by the coil assembly, avoiding additional space requirements.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Manufacturing precision

If three-dimensional modeling software is used for cavity design, then the design precision is improved, but the manufacturing complexity increases

Engineering Contradiction:
Improvecavity design precisionVSAvoidmanufacturing complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent replaces traditional manual or mechanical design methods with three-dimensional modeling software for cavity design. This digital modeling approach enables precise cavity geometry to be defined and visualized before manufacturing, improving design precision while the subsequent use of standard manufacturing processes maintains ease of production.

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 design achieves high power handling capability, low thermal resistance, and cost-effectiveness by using a resonator with a cavity-enclosing shape and integrated capacitors, suitable for HR and MAS MR applications.

Implementation Method 1

high-frequency bandpass filter for an mr apparatus with coil body having a cavity

Methodology Applied
Scientific EffectElectromagnetic resonance: Resonance

Implementation Method 2

coil body having a cavity

Methodology Applied
Scientific EffectElectromagnetic field confinement: Waveguide

Data Source

PatentEP4646762B1High-frequency bandpass filter for an mr apparatus with coil body having a cavity, mr apparatus
Publication Date: 2026.04.08 BRUKER SWITZERLAND AG
  • EP4646762B1 patent drawingFigure 1
  • EP4646762B1 patent drawingFigure 2
  • EP4646762B1 patent drawingFigure 3

AI summary

The invention relates to a high-frequency bandpass filter for an MR apparatus, in particular for a transmission and/or receiving arrangement of the MR apparatus, comprising a resonator arrangement with a signal input, a signal output and at least one resonator, wherein each resonator has a capacitor which is connected in parallel to an inductor, characterised in that the inductor comprises an electrically conductive coil body having a cavity which is closed in a substantially HF-tight manner. As a result, an HF bandpass filter of high quality, high electric load-bearing capacity and simultaneously a low impedance level is achieved which can be produced simply and at low cost.