Distributed Power Amplifiers for MRI Coil Signal Loss Reduction
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Solution Overview
Problem
Conventional MRI machines face inefficiencies in connecting and transmitting high-power RF signals to antenna arrays due to significant signal losses in coaxial cables and combiner circuits, limiting flexibility and increasing costs.
Innovation Solution
Distributing power amplifiers directly to coil elements within the RF-coil device, using active electronic devices like field-effect transistors thermally coupled to the coils, which reduces the need for high-power coaxial cables and allows for wireless signal transmission, enabling more flexible circuit layouts and improved heat management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional coaxial cables and combiner circuits are used to transmit high-power RF signals, then signal transmission is achieved, but significant signal losses occur and costs increase
Solution Approach 1:
The patent divides the RF coil system into multiple independent elements, each with its own power amplifier. Instead of using a single centralized amplifier with combiners and coaxial cables, the system segments the amplification function across multiple distributed elements, eliminating the need for high-power cable transmission and signal combining infrastructure.
Solution Approach 2:
The patent extracts the power amplifier function from the centralized control room and places it directly at each coil element within the magnet bore. This removes the dependency on high-power coaxial cable transmission and combiner circuits, as each element independently generates its own RF signal.
2Adaptability or versatility
If power amplifiers are distributed to coil elements, then flexibility in coil positioning is enhanced, but device complexity increases
Solution Approach 1:
The patent merges the power amplifier and coil element into a single integrated unit. By combining these functions at each element, the system gains positioning flexibility while avoiding the complexity of distributing separate amplifier and coil components through complex cabling infrastructure.
Solution Approach 2:
Each coil element is designed to be a self-contained unit that can independently perform both amplification and radiation functions. This universal design allows elements to be positioned flexibly throughout the magnet bore without requiring specialized cabling or connection infrastructure for each position.
3Temperature
If active electronic devices are thermally coupled to coil elements, then heat management is improved, but manufacturing complexity increases
Solution Approach 1:
The coil elements themselves serve as heat sinks for the power amplifiers. By thermally coupling the amplifiers to the coil elements, the system uses the existing coil structure to dissipate heat, eliminating the need for separate cooling infrastructure and simplifying the overall thermal management design.
Solution Approach 2:
The thermal management function is merged with the existing coil element structure. Rather than adding separate cooling systems, the design combines the amplifier thermal dissipation requirements with the coil element's physical structure, using the coil's mass and surface area for heat sinking.
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
This approach minimizes signal losses, reduces costs, enhances flexibility in coil positioning, and provides better patient comfort by eliminating massive cabling, while allowing for advanced features like automatic tuning and impedance matching.
Implementation Method 1
active electronic devices like field-effect transistors thermally coupled to the coils
Data Source
AI summary
Apparatus and method that includes amplifiers for transceiver antenna elements, and more specifically to power amplifying an RF (radio frequency) signal using a distributed power amplifier having electronic devices (such as field-effect transistors) that are thermally and/or mechanically connected to each one of a plurality of antenna elements (also called coil elements) to form a hybrid coil-amplifier (e.g., for use in a magnetic-resonance (MR) imaging or spectroscopy machine), and that is optionally adjusted from a remote location, optionally including remotely adjusting its gains, electrical resistances, inductances, and/or capacitances (which controls the magnitude, phase, frequency, spatial profile, and temporal profile of the RF signal)—and, in some embodiments, the components are compatible with, and function in, high fields (such as a magnetic field of up to and exceeding one tesla or even ten tesla or more and/or an electric field of many thousands of volts per meter).