Multi-Resonator Spin Resonance Sensor for Fast Banknote Testing
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Solution Overview
Problem
Existing banknote processing machines struggle with short measurement times that do not allow for spectrally highly resolved and/or broadband measurements of spin resonance features, making it difficult to distinguish between different currencies or denominations.
Innovation Solution
A sensor element with multiple stripline resonators arranged at different positions in an inhomogeneous magnetic field, allowing simultaneous measurement of spin resonance at various polarization field strengths, thereby increasing spectral resolution and reducing measurement time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single stripline resonator is used for measurement, then the device complexity is low, but the spectral resolution is insufficient and measurement time is too long to capture complete spin resonance spectra
Solution Approach 1:
The patent divides the measurement function across multiple stripline resonators (at least two) positioned at different locations in the air gap. Each resonator measures spin resonance at a different polarization field strength, collectively capturing the complete spectrum that a single resonator could not obtain within the short measurement time.
Solution Approach 2:
The patent introduces spatial positioning as an additional dimension to the measurement system. By arranging resonators at different positions along the magnetic field gradient, the system transforms a temporal measurement problem (scanning through frequencies over time) into a spatial measurement problem (simultaneous measurements at different positions), thereby achieving complete spectral coverage in short time.
2Productivity
If the measurement time is shortened for high-speed processing, then productivity increases, but the spectral resolution deteriorates making it impossible to distinguish between different currencies or denominations
Solution Approach 1:
The patent enables continuous spectral measurement by having multiple resonators simultaneously active at different field positions. This eliminates the need for sequential frequency sweeping, allowing the complete spin resonance spectrum to be captured in a single snapshot during high-speed banknote transport, thus maintaining both speed and resolution.
Solution Approach 2:
The patent pre-positions multiple resonators at specific locations where they will encounter different polarization field strengths as the banknote passes through. This preliminary spatial arrangement ensures that when the banknote moves through the system at high speed, all necessary spectral information is already positioned to be captured simultaneously without requiring time-consuming sequential measurements.
3Adaptability or versatility
If multiple resonators are positioned at different locations, then complete spectral coverage is achieved, but the device complexity and inhomogeneous field requirements increase
Solution Approach 1:
The patent creates an inhomogeneous magnetic field where different regions (positions in the air gap) have different polarization field strengths. This local variation in field quality allows each resonator positioned at a specific location to operate at a different effective frequency, enabling simultaneous spectral coverage without requiring complex tuning mechanisms.
Solution Approach 2:
The patent replaces the mechanical approach of moving a single resonator through different field positions (or sweeping frequencies over time) with a static multi-resonator configuration. The spatial arrangement of resonators substitutes for temporal scanning mechanisms, simplifying the dynamic requirements while achieving complete spectral coverage.
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 high spectral resolution and shorter measurement times, facilitating accurate authentication of banknotes by capturing spin resonance signatures with improved efficiency.
Implementation Method 1
a polarization device for creating a static magnetic flux in the air gap
Implementation Method 2
to excite transitions between the split spin energy levels of the spin resonance signature substances
Implementation Method 3
the excitation field oscillates at the resonant frequency of the material, which is also referred to as Larmor frequency and which is proportional to the polarization field B0
Implementation Method 4
If the wavelength λ of the incoupled radiofrequency signal matches the dimension 1 of the conductive structure during the authenticity test, then a standing wave can form in the resonator
Implementation Method 5
A second magnetic field is formed by a modulation field Bmod which likewise extends parallel to the z-axis and typically has a frequency fmod in the kHz range
Data Source
AI summary
A sensor element is for testing a planar data carrier with a spin resonance feature. The sensor element includes a magnetic core having an air gap into which the planar data carrier can be inserted for testing purposes, 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 has at least two stripline resonators positioned at different positions in the air gap. The polarization device generates an in-homogeneous magnetic flux in the air gap so that the static magnetic flux has a first field strength at the position of a first stripline resonator and a second, different field strength at the position of a second stripline resonator.