RF Transmission Line with Integrated Transformers
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Solution Overview
Problem
Existing connection leads or transmission lines for MR imaging systems are not adequately safe when guided through RF fields, as they can induce RF common mode signals leading to heating and potential burning, and are costly and mechanically unreliable for use with invasive devices like catheters.
Innovation Solution
A miniaturized electrically conductive link or transmission line with integrated transformers and a low dielectric constant, manufactured using PCB techniques, which minimizes signal loss and mechanical stress, and is designed for safe use in RF fields with dimensions suitable for invasive applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional connection leads are used in RF fields, then connection functionality is provided, but RF common mode signals are induced causing heating and potential burning
Solution Approach 1:
A transformer is introduced as an intermediary component between two lead segments. The transformer couples the segments magnetically while blocking RF common mode signals from propagating along the lead, thereby preventing heating and burning risks without compromising connection functionality
Solution Approach 2:
The connection lead is divided into multiple segments (first lead segment and second lead segment) connected by a transformer. This segmentation allows the lead to maintain electrical connectivity while the transformer acts as a barrier against RF common mode signals, improving safety in RF fields
2Object-affected harmful factors
If connection leads are made safe for RF fields using traditional methods, then heating risks are reduced, but cost and mechanical reliability decrease
Solution Approach 1:
Traditional mechanical safety methods (such as complex shielding structures or multiple discrete components) are replaced by integrating the transformer directly into the lead construction using PCB techniques. This substitution simplifies manufacturing, reduces cost, and improves mechanical reliability while maintaining RF safety
Solution Approach 2:
The transformer is integrated directly into the connection lead structure, merging the safety function with the connection function into a single unified component. This integration eliminates the need for separate safety mechanisms, reducing manufacturing complexity and cost while improving mechanical reliability
3Object-affected harmful factors
If transformers are integrated into connection leads, then RF common mode signals are suppressed, but signal loss and mechanical stress increase
Solution Approach 1:
The physical parameters of the transformer and lead segments are optimized to minimize signal loss. By carefully selecting transformer coupling coefficients, lead segment lengths, and impedance values, the design achieves effective RF common mode suppression while maintaining acceptable differential mode signal transmission with minimal loss
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 effectively suppresses RF common mode signals, reduces heating risks, and is cost-effective for disposable catheters, while maintaining low signal loss and suitable mechanical properties for invasive applications.
Implementation Method 1
comprising at least one transformer (41, 83) for coupling at least two lead segments (21, 80a, 80b) of the line
Implementation Method 2
at least one first and a second stripline (21, 80a, 80b) each comprising a first and a second metal layer (81, 82) on a dielectric substrate (63) with a low dielectric constant
Data Source
AI summary
An electrically conductive link (connection lead) or transmission line (13) including at least one transformer (41, 42; 83) for coupling at least two lead segments (51, 52; 81, 82) of the line (13) and for providing safety of the line when guided through a RF field. These lines are especially provided for use with a magnetic resonance (MR) imaging system and for connecting an electrical device (10), especially a catheter or another invasive device for the examination of a human body, to a connection unit (12) such as, for example, a power supply or control unit outside the examination zone (1) without imposing the risk of disturbances and/or destruction of the electrical device and/or the connection unit and of burning a patient (P) by a heating of the line when guided through RF fields.