RF Coil Array Ground Loop Self-Resonance Frequency Tuning
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Solution Overview
Problem
In MRI systems, coaxial cables between RF coils cause cross-coupling interference, leading to performance degradation in RF coil arrays, and the precise placement of baluns to mitigate this is time-consuming and inefficient.
Innovation Solution
A radio frequency (RF) coil array with a common ground connection selectively positioned along the cables to form a ground loop with a self-resonance frequency different from the imaging frequency, where the grounding point is based on the wavelength of the RF energy, reducing interference and improving performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If baluns are placed in series with coaxial cables to reduce cross coupling effects, then interference suppression is improved, but device complexity and installation time increase due to precise placement requirements
Solution Approach 1:
The patent extracts the harmful ground loop from the system by selectively positioning the common ground connection to form a ground loop with self-resonance frequency different from the imaging frequency, thereby removing the cross-coupling interference problem without requiring additional balun components
Solution Approach 2:
The patent changes the frequency parameter of the ground loop by adjusting the position of the common ground connection along the cable, setting its self-resonance frequency to differ from the imaging frequency, which transforms the ground loop from a harmful element into a beneficial one that suppresses cross-coupling
2Object-affected harmful factors
If baluns are used to suppress cross coupling effects, then signal interference is reduced, but installation efficiency decreases due to trial and error placement process
Solution Approach 1:
The patent performs preliminary action by pre-calculating and pre-positioning the common ground connection at a specific location along the cable that creates the desired self-resonance frequency, eliminating the need for trial-and-error adjustment during installation
3Reliability
If common ground connection is positioned at specific locations to form ground loops, then self-resonance frequency tuning is improved, but device complexity increases due to precise positioning requirements
Solution Approach 1:
The patent changes the position parameter of the common ground connection along the cable to adjust the self-resonance frequency of the ground loop, providing a simple method to tune the frequency without adding complex adjustment mechanisms
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 reduces signal loss and interference by tuning the self-resonance frequency of the ground loop to be less than the imaging frequency, enhancing the performance of the RF coil array and simplifying the placement process.
Implementation Method 1
The common ground connection is selectively positioned at a grounding point along lengths of the first and second cables to form a ground loop having a select self-resonance frequency (SRF) that differs from the imaging frequency
Data Source
AI summary
In accordance with various embodiments, a radio frequency (RF) coil array for use in a magnetic resonance imaging (MRI) system includes at least first and second RF coils. Each of the RF coils have a main body loop configured to at least one of transmit or receive RF energy at an operating imaging frequency in connection with acquiring MRI image data for an MRI system. The RF coil array also includes first and second cables configured to electrically couple the first and second RF coils, respectively, to a system interface. The RF coil array also includes a common ground connection between the first and second cables. The common ground connection is selectively positioned at a grounding point along lengths of the first and second cables to form a ground loop having a select self-resonance frequency (SRF) that differs from the imaging frequency of the MRI system.