Air-Gap Spin Resonance Sensor With Multi-Frequency Resonators
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Solution Overview
Problem
Existing banknote processing machines struggle with high-speed authentication that requires short measuring times, which are insufficient for complete spectral resolution of spin resonance features, limiting the ability to distinguish between different currencies or denominations.
Innovation Solution
A sensor element with multiple stripline resonators operating at different excitation frequencies, allowing simultaneous measurement at multiple frequencies for higher spectral resolution and shorter measurement times, using a magnetic core, polarization device, and resonator device with a one-dimensional or multi-track array of stripline resonators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single stripline resonator is used for spin resonance measurement, then the measurement setup is simple, but the spectral resolution is insufficient and measurement time is too long for high-speed authentication
Solution Approach 1:
The patent divides a single resonator into multiple segmented stripline resonators operating at different excitation frequencies. Each resonator segment is tuned to a specific frequency, allowing simultaneous measurement across multiple frequency points. This segmentation enables high spectral resolution without requiring a single complex broadband resonator, thus resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The patent transitions from a single-frequency measurement approach to a multi-frequency parallel measurement approach by adding the frequency dimension. Multiple resonators operate simultaneously at different frequencies, transforming the measurement process from sequential (time-consuming) to parallel (fast), thereby achieving both high spectral resolution and reduced measurement time while maintaining reasonable device complexity.
2Loss of information
If a B0-ramp procedure is used to record the complete spin resonance spectrum, then spectral information is complete, but the measurement time is too long for high-speed banknote processing
Solution Approach 1:
The patent applies preliminary action by pre-tuning multiple resonators to different excitation frequencies before the measurement process. This allows the system to immediately capture spectral information across multiple frequency points without needing to perform a time-consuming B0-ramp procedure. The spectral information is obtained in advance through the multi-frequency resonator configuration, eliminating the need for sequential sweeping and dramatically reducing measurement time while maintaining complete spectral information.
Solution Approach 2:
The patent enables continuous useful action by having multiple resonators operate simultaneously and continuously at their respective resonant frequencies. Unlike the B0-ramp method which sequentially traverses frequency points, the multi-resonator system maintains continuous measurement activity across the entire spectral range of interest, capturing complete spectral information without interruption or time delay.
3Productivity
If multiple resonators operate at different frequencies, then spectral resolution and measurement speed improve, but the device complexity and signal coordination become more challenging
Solution Approach 1:
The patent applies local quality by assigning each resonator a specific local function - each is optimized for a particular excitation frequency range. This localized optimization allows each resonator to operate independently at its peak performance without interfering with others, simplifying the coordination problem. The system achieves high productivity through this division of labor, where each resonator handles a specific spectral portion, and the overall device complexity is managed through modular, frequency-specific design rather than a single complex broadband system.
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
Enables high-resolution and broadband spin resonance measurement in a short time, reducing the need for field ramp measurements and improving the ability to authenticate banknotes with diverse spectral signatures.
Implementation Method 1
a polarization device for generating a static magnetic flux in the air gap
Implementation Method 2
an excitation field B1 is provided, which is polarized perpendicular to the B0 direction. The excitation field oscillates at the resonance frequency of the material, which is also referred to as the Larmor frequency
Implementation Method 3
If the wavelength λ of the coupled-in high-frequency signal matches the dimension 1 of the conducting structure during the authenticity test, a standing wave can form in the resonator and the stripline resonator is in resonance at the excitation frequency associated with the wavelength λ
Data Source
AI summary
A sensor element for testing a flat-surface data carrier has a spin resonance feature. The sensor element includes a magnetic core with an air gap, into which the flat-surface data carrier can be inserted for testing, a polarization device for generating a static magnetic flux in the air gap, and a resonator device for exciting the spin resonance feature of the data carrier to be tested in the air gap. The resonator device contains at least two stripline resonators, which are designed and configured to be operated at different excitation frequencies.