Passive Wireless Coil Marker With Piezoelectric Resonant Tracking
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Solution Overview
Problem
Existing tracking and sensing technologies for small medical devices face challenges in achieving high accuracy due to limitations in signal-to-noise ratio and quality factor, requiring complex and costly readout systems, especially with magnetic coil resonators.
Innovation Solution
A marker device combining a magnetic coil resonator with a piezoelectric resonator element, utilizing a high-quality factor circuit to enable accurate tracking and sensing of physical parameters using a simple readout system, with optional capacitive elements and soft magnetic materials for enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic coil resonators are used for tracking and sensing, then signal-to-noise ratio improves at larger sizes, but quality factor becomes very low requiring fast and complex readout systems
Solution Approach 1:
The patent combines a magnetic coil resonator with a piezoelectric resonator into a single integrated sensing unit. The piezoelectric resonator generates mechanical oscillations in response to magnetic field changes, which are then detected by the magnetic coil resonator. This merging allows the system to achieve high signal-to-noise ratio through the magnetic coil resonator while the piezoelectric resonator provides the oscillation source, eliminating the need for complex fast readout systems.
Solution Approach 2:
The piezoelectric resonator acts as an intermediary element that converts magnetic field changes into mechanical oscillations. These mechanical oscillations then modulate the magnetic coil resonator's signal, creating a detectable response without requiring direct fast switching between excitation and detection modes. This intermediary mechanism enables accurate tracking with simpler readout electronics.
2Measurement precision
If magnetic coil resonators are used for accurate tracking, then measurement accuracy improves, but switching speed must be very fast increasing cost and complexity
Solution Approach 1:
The piezoelectric resonator generates periodic mechanical oscillations at its resonant frequency in response to magnetic field changes. This periodic action creates a continuous oscillating signal from the magnetic coil resonator that can be detected without fast switching. The tracking system can integrate signals over multiple oscillation cycles, achieving high accuracy with slower, simpler readout electronics.
3Adaptability or versatility
If micro-magnetic oscillators are used for tracking small devices, then tracking capability is achieved, but signal-to-noise ratio scales poorly with device size
Solution Approach 1:
The patent changes the operating parameters by using a piezoelectric resonator that responds to magnetic field changes with mechanical oscillations. This parameter change allows the sensing unit to generate its own oscillating signal rather than relying on externally driven micro-magnetic oscillators. The piezoelectric effect provides a stronger, more scalable signal that maintains good signal-to-noise ratio across different device sizes.
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 provides high-accuracy tracking and sensing capabilities in various conditions, reducing the need for complex electronics and minimizing damage risk, while allowing for gradient-based position determination and sensitive parameter detection.
Implementation Method 1
the coil element is configured to transduce an external magnetic or electromagnetic excitation field into an output voltage
Implementation Method 2
the resonator element is configured to transduce the output voltage into respective mechanical oscillations in a resonant mode
Implementation Method 3
to provide a piezoelectric voltage to the coil element
Implementation Method 4
the coil element is configured to transduce the piezoelectric voltage into a magnetic field
Data Source
AI summary
A wireless passive marker device (1) to be tracked and a respective tracking system (3) are provided which make use of a sensing unit (10) comprising a resonator element (11) with piezoelectric properties and a coil element (13), whereby an externally applied excitation field having a particular frequency is applied to act on the sensing unit (10) and wherein the sensing unit (10) responds to the externally applied excitation field by the resonator element (11) performing persisting mechanical oscillations in resonant mode, the persisting mechanical oscillations resulting in a piezoelectric voltage causing the coil element (13) to generate a magnetic field that may then be detected by the tracking system (3) and used for determining the position of the marker device (1) and/or sensing a physical property in the surrounding environment of the marker device (1).