PCB Shielding for MR Tomography Standing Wave Suppression
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Solution Overview
Problem
Existing standing wave traps for MR tomography are expensive, require manual assembly, have high space requirements, and can cause interference due to discontinuities in shielded cables, leading to potential patient safety risks and image quality issues.
Innovation Solution
A printed circuit board design with terminations for shielded cables, featuring a basic and auxiliary shield impervious to magnetic resonance frequencies, and integrated baluns to suppress standing waves, allowing for automated manufacturing and reduced space usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standing wave traps are wound manually and soldered onto shielded cables, then shielding effectiveness is improved, but manufacturing cost increases and manufacturing complexity increases
Solution Approach 1:
The patent merges the shielding function and standing wave suppression function into a single integrated structure. The shielded cable itself is designed with specific geometric configurations (such as twisted pairs or coaxial structures) that inherently suppress standing waves, eliminating the need for separate manual standing wave traps. This integration maintains shielding effectiveness while dramatically reducing manufacturing complexity and cost.
Solution Approach 2:
The patent replaces manual mechanical processes (hand-winding standing wave traps, manual soldering) with automated manufacturing processes. The shielded cable structure is designed to be manufactured using standard automated PCB fabrication techniques, where the shielding and standing wave suppression features are created through precise pattern definition and material deposition, eliminating manual assembly operations.
2Reliability
If standing wave traps are wound manually and soldered onto shielded cables, then shielding effectiveness is improved, but device complexity increases
Solution Approach 1:
The patent merges the shielding function and standing wave suppression function into a single integrated structure. The shielded cable itself is designed with specific geometric configurations (such as twisted pairs or coaxial structures) that inherently suppress standing waves, eliminating the need for separate manual standing wave traps. This integration maintains shielding effectiveness while dramatically reducing manufacturing complexity and cost.
3Ease of operation
If shielded cables are routed in proximity to antennas, then cable routing flexibility is improved, but interference increases due to preamplified signal feedback
Solution Approach 1:
The patent introduces an intermediary structure - a ground plane or reference shield - positioned between the shielded cable and the antenna. This intermediary element provides a reference potential that prevents the preamplified signal from coupling back into the antenna, thereby eliminating feedback interference while allowing the cable to be routed in close proximity to the antenna for flexibility.
4Ease of operation
If discontinuities are introduced in shielded cables for signal routing, then cable routing flexibility is improved, but interference increases due to signal leakage
Solution Approach 1:
The patent introduces an intermediary structure - a ground plane or reference shield - positioned between the shielded cable and the antenna. This intermediary element provides a reference potential that prevents the preamplified signal from coupling back into the antenna, thereby eliminating feedback interference while allowing the cable to be routed in close proximity to the antenna for flexibility.
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 simplifies cable routing, reduces space requirements, and minimizes interference, enhancing patient safety and image quality while enabling more efficient use of space and manufacturing automation.
Implementation Method 1
A basic shield (13) that is impervious to frequencies in a magnetic resonance range is disposed on the top side (1) and/or the bottom side (2). An auxiliary shield (14) that is electrically connected to the basic shield (13) and is impervious to frequencies in the magnetic resonance range is disposed on the narrow sides (5).
Implementation Method 2
At least one balun (17) is mounted onto the basic shield (13) and/or the auxiliary shield (14) for the purpose of suppressing standing waves.
Data Source
AI summary
A printed circuit board (PCB) is flat, providing a top side and a bottom side. A plurality of terminations is disposed on the top side in proximity to one end face of the PCB. Each termination has at least one contact that is connected to a respective conductor track of the PCB. The respective conductor track is connected to a respective local coil or to a contact disposed on the top side or the bottom side of a respective further termination. The local coil and/or at least one of the further terminations are disposed in proximity to the other end face. A basic shield impervious to frequencies in a magnetic resonance range is disposed on the top side and/or the bottom side, and an auxiliary shield electrically connected to the basic shield and impervious to frequencies in the magnetic resonance range is disposed on narrow sides of the PCB.