Multi-Layer Grounding Cradle for MRI Preamplifier Stability
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Solution Overview
Problem
The grounding of MRI preamplifiers is difficult to control due to their close proximity to receiving antennas, leading to signal-to-noise degradation and oscillations in high-density coils, which affects the stability and performance of the preamplifiers.
Innovation Solution
A multi-layer cradle is designed with a first and second ground plane, dielectric material, and fence vias to stabilize the grounding of the preamplifiers, reducing edge currents and oscillations by connecting the ground plane to a current sink via fence vias, thereby enhancing the stability of the preamplifiers and RF coils.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the preamplifier is placed close to the receiving antenna to overcome signal-to-noise degradation, then the signal-to-noise ratio is improved, but the grounding control becomes difficult
Solution Approach 1:
The grounding structure is segmented into multiple layers (first ground plane, second ground plane) separated by dielectric material, with fence vias creating distinct grounding zones. This segmentation allows independent control of grounding characteristics at different locations and frequencies, resolving the grounding control difficulty while maintaining close proximity to the antenna.
Solution Approach 2:
The invention transitions from a single-plane grounding approach to a multi-layer three-dimensional grounding structure. By adding the vertical dimension with stacked ground planes and dielectric layers, the design achieves better grounding control and electromagnetic isolation while keeping the preamplifier close to the antenna.
2Power
If the preamplifier is placed close to the receiving antenna to amplify the signal, then the signal amplification is improved, but oscillations occur in high-density coils
Solution Approach 1:
The multi-layer cradle with dielectric material and fence vias acts as an intermediary structure between the preamplifier and the surrounding RF environment. It provides electromagnetic isolation and controls edge currents, preventing oscillations while allowing the preamplifier to remain close to the antenna for effective signal amplification.
Solution Approach 2:
The grounding structure implements local quality variations through fence vias that create specific electromagnetic characteristics at different locations. The first ground plane, second ground plane, and dielectric material create localized electromagnetic environments that suppress oscillations in high-density coil configurations.
3Measurement precision
If high-density coils are used to increase coil feedback, then the spatial resolution is improved, but the coil feedback causes oscillations
Solution Approach 1:
The invention changes the electromagnetic parameters of the grounding structure by using multiple ground planes separated by dielectric material with specific permittivity. The fence vias create controlled impedance transitions and electromagnetic isolation, allowing high-density coil configurations to achieve improved spatial resolution without oscillations.
Data Source
AI summary
A multi-layer cradle comprises a first layer comprising first and second contact pads configured to be electrically coupled to a signal input and a signal output of the electronic component, respectively. The first layer also comprises a first ground plane configured to be electrically coupled to a ground of the electronic component and a first fence positioned about the first ground plane. The first ground plane is positioned at least between the first and second contact pads. A second layer comprising a second ground plane is also included. The cradle further comprises a first dielectric material positioned between the first and second layers, a ground plane via extending through the first dielectric material and electrically coupled to the first and second ground planes, and a plurality of fence vias extending through the first dielectric material and electrically coupled to the first fence and to second ground plane.