PCB RF Power Converter With Planar Inductors for Compact MRI Matching
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Solution Overview
Problem
Current radio-frequency power converters for magnetic resonance imaging face challenges such as size limitations, inefficiency due to magnetic core overheating, and the difficulty in using standard lumped capacitors and inductors, which hinder the miniaturization and performance consistency of MRI systems.
Innovation Solution
A radio-frequency power converter using a printed circuit board with planar spiral inductors and standard capacitors, configured as a power distributor or synthesizer, which overcomes the limitations by achieving a compact structure and efficient performance without the need for magnetic cores, utilizing a printed circuit board with multiple layers and standard capacitive elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional Wilkinson-type power distributor or synthesizer is used with transmission lines, then the device can achieve proper impedance matching and signal distribution, but the device size becomes very large due to the quarter-wavelength transmission line requirement
Solution Approach 1:
The patent transforms the distributed transmission line structure into a lumped element equivalent circuit, changing the physical parameters from wavelength-scale dimensions to much smaller lumped inductance and capacitance values. This allows the same electrical function to be achieved with dramatically reduced physical size while maintaining impedance matching characteristics.
Solution Approach 2:
The patent creates an equivalent circuit model that copies the electrical behavior of the traditional Wilkinson circuit. By using lumped elements that replicate the impedance matching and signal distribution functions of the transmission line version, the invention achieves the same performance without the size penalty.
2Area of stationary object
If standard lumped capacitors and inductors are used in the Lumped Wilkinson power distributor, then the device size is reduced, but standard components cannot be applied and manual manufacturing is required
Solution Approach 1:
The patent designs the lumped inductors and capacitors with standardized values and configurations that can be manufactured using conventional PCB fabrication processes. This universal design approach allows the same component types and values to be used across different frequency applications, eliminating the need for custom manual manufacturing while maintaining compact size.
3Area of stationary object
If a short transmission line is sheathed with a magnetic core to achieve compact size, then the device structure becomes small, but transmission efficiency is greatly compromised due to magnetic core loss and overheating
Solution Approach 1:
The patent removes the magnetic core from the design entirely, extracting the problematic source of energy loss and overheating. By using air-core or non-magnetic implementations of the lumped inductors, the invention eliminates magnetic core losses while maintaining the compact size advantage, thus resolving the contradiction between size reduction and efficiency preservation.
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 enables a compact, efficient, and consistent radio-frequency power distribution and synthesis, reducing size and overheating issues while maintaining high performance, thus enhancing the MRI system's efficiency and reliability.
Implementation Method 1
A plurality of planar spiral inductors connected in parallel are formed on the first circuit layer. One ends of the plurality of inductors are connected to each other and respectively connected to one end of a first capacitor
Implementation Method 2
One ends of the plurality of inductors are connected to each other and respectively connected to one end of a first capacitor; the other ends of the plurality of inductors are respectively connected to one ends of a plurality of second capacitors
Data Source
AI summary
A radio-frequency power converter and a radio-frequency transmission system for magnetic resonance imaging are provided in embodiments of the present invention. The radio-frequency power converter comprises a printed circuit board, the printed circuit board comprises a first circuit layer, a ground layer, and one or a plurality of intermediate layers located between the first circuit layer and the ground layer. A plurality of planar spiral inductors connected in parallel are formed on the first circuit layer. One ends of the plurality of inductors are connected to each other and respectively connected to one end of a first capacitor, the other ends of the plurality of inductors are respectively connected to one ends of a plurality of second capacitors, and the other ends of the plurality of second capacitors are all grounded.