Shielded Electronic Assembly With Filtered MRI Cable Feedthrough
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Solution Overview
Problem
Existing electromagnetic shielding methods fail to effectively prevent the external radiation of radiofrequency energy generated by electronic devices within magnetic resonance imaging systems due to the presence of electrical conductors extending from shielded regions, which act as radiators and emit unwanted electromagnetic interference.
Innovation Solution
An electromagnetically shielded electronic assembly is designed with a filter residing in a secondary shielded region, electrically connected to the electromagnetic shielding, while the electronic device remains non-conductively connected, directing radiofrequency energy within the blocking frequency band to the shielding, thereby preventing external radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If electrical conductors extend from shielded regions to external components, then electrical connection and signal transmission are enabled, but external radiation of radiofrequency energy occurs and electromagnetic interference is generated
Solution Approach 1:
A filter serves as an intermediary component between the shielded electronic device and external electrical conductors. The filter is positioned within a secondary shielded region and selectively blocks radiofrequency energy while allowing lower frequency signals to pass through, thereby maintaining electrical connection functionality while preventing harmful electromagnetic radiation
Solution Approach 2:
The shielding structure is divided into two distinct regions: a primary shielded region containing the electronic device and a secondary shielded region containing the filter. This segmentation allows different shielding strategies to be applied to each region, with the filter region providing an additional layer of protection against radiofrequency radiation while maintaining necessary electrical connections
2Object-affected harmful factors
If electromagnetic shielding is implemented to block radiofrequency radiation, then electromagnetic interference is reduced, but electrical conductors cannot extend externally without creating radiation pathways
Solution Approach 1:
The filter acts as a mediator that reconciles the conflicting requirements of electromagnetic shielding and electrical connection. It provides a controlled pathway for electrical signals while blocking radiofrequency radiation, enabling the system to maintain both shielding effectiveness and external connectivity
Solution Approach 2:
Different regions of the electrical connection pathway are assigned different electromagnetic properties. The secondary shielded region and filter provide high attenuation for radiofrequency signals, while allowing passage of lower frequency control signals, creating localized electromagnetic characteristics optimized for different signal types
3Object-generated harmful factors
If electronic devices are housed within electromagnetic shielding, then radiofrequency radiation is contained, but electrical conductors extending externally act as radiators and emit interference
Solution Approach 1:
The filter serves as an intermediary that decouples the electronic device from direct electrical connection to external components. By positioning the filter in the secondary shielded region and having it electrically contact the shielding, external electrical connections can be made without creating direct radiation pathways from the electronic device
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 configuration significantly reduces external radiation of radiofrequency energy, enhancing the integrity of magnetic resonance imaging by minimizing electromagnetic interference.
Implementation Method 1
a filter residing within the second electromagnetically shielded region, the filter coupling the electronic device to the electrical conductor through conductive pathways extending through respective portals within the electromagnetic shielding defining the second electromagnetically shielded region
Implementation Method 2
electromagnetic shielding defining a first electromagnetically shielded region and a second electromagnetically shielded region, where the first electromagnetically shielded region and the second electromagnetically shielded region are electromagnetically shielded within at least an operating bandwidth of the magnetic resonance imaging scanner
Data Source
AI summary
An electromagnetically shielded electronic assembly is disclosed in which electromagnetic shielding and filtering is provided to prevent unwanted radiofrequency energy, generated from an electric device residing within the assembly, from radiating externally. The electronic device resides within a primary shielded region and is coupled, through a filter, to an external electrical conductor that extends externally from the shielding. The filter resides within a secondary shielded region that is electromagnetically shielded from the primary shielded region, with the filter electrically contacting the electromagnetic shielding within the secondary shielding region. The electronic device is housed without being brought into electrically conductive contact with the electromagnetic shielding, such that radiofrequency signals generated by the electronic device can be directed, within a blocking frequency band of the filter, to the electromagnetic shielding, thereby reducing or preventing the internally generated radiofrequency energy, within the blocking frequency band of the filter, from radiating externally.