Stripline Resonator Array for High-SNR Spin Resonance Testing
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Solution Overview
Problem
Existing sensor elements for testing data carriers with spin resonance features, such as banknotes, suffer from limited signal-to-noise ratio, inability to measure non-adjacent positions, and limitations in increasing signal strength without causing saturation or impedance mismatch.
Innovation Solution
A sensor element with a magnetic core and a resonator unit comprising multiple stripline resonators, all fed by a single signal source, allowing simultaneous operation and distributed power supply to enhance signal-to-noise ratio and enable measurement of both contiguous and non-adjacent features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the resonator size is increased to improve signal-to-noise ratio, then the sensitive region increases, but the resonant frequency changes and the quality factor drops
Solution Approach 1:
The patent divides a single large resonator into multiple smaller resonators (e.g., four resonators arranged in a 2x2 array). Each resonator maintains its own resonant frequency and quality factor, while collectively they provide a larger sensitive region. The signal-to-noise ratio improves because the sensitive volume is increased through the array configuration, not by enlarging individual resonators.
Solution Approach 2:
Multiple resonators are combined into a single resonator array that functions as one measurement system. The resonators are positioned close to each other with their sensitive regions overlapping or adjacent, creating a combined sensitive volume that is larger than any single resonator. This merging approach allows the system to achieve high signal-to-noise ratio while maintaining the resonant frequency and quality factor of individual resonators.
2Measurement precision
If the resonator is operated in a higher spatial mode to increase sensitive region, then the signal-to-noise ratio improves, but the quality factor drops and signal strength reduces
Solution Approach 1:
Instead of operating a single resonator in a higher spatial mode, the patent uses multiple resonators operating in their fundamental modes. Each resonator in the array operates in its lowest spatial mode, which maintains high quality factor and signal strength. The collective array provides the increased sensitive region that would otherwise require higher spatial modes.
3Measurement precision
If the stripline resonator is broadened to maintain constant resonant frequency, then the sensitive region increases, but impedance matching becomes difficult
Solution Approach 1:
The patent avoids broadening individual resonators by instead using multiple resonators of standard dimensions. Each resonator in the array maintains its standard impedance characteristics, making impedance matching straightforward. The increased sensitive region is achieved through the array configuration rather than by enlarging individual elements.
4Measurement precision
If the excitation signal power is increased beyond the optimal limit, then the signal strength increases, but signal saturation or distortion occurs
Solution Approach 1:
Multiple resonators are fed simultaneously from a single signal source, allowing the total excitation power to be distributed across all resonators. This enables the system to utilize higher total power without saturating any individual resonator, as the power is divided among multiple elements. The signal accuracy is maintained because no single resonator operates beyond its optimal power limit.
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 significantly increases the signal-to-noise ratio and allows for higher excitation power without saturation, enabling efficient detection of spin resonance features across larger areas of the data carrier.
Implementation Method 1
a polarization device for creating a static magnetic flux in the air gap
Implementation Method 2
the resonator unit is used to excite the spin resonance feature of the data carrier to be tested in the air gap
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
The spin resonance signatures that can be used for authenticity testing include, in particular, nuclear magnetic resonance (NMR) effects
Implementation Method 5
electron spin resonance (ESR) effects
Implementation Method 6
ferromagnetic resonance (FMR) effects
Data Source
AI summary
A sensor element is for testing a flat data carrier having a spin resonance feature. The sensor element includes a magnetic core having an air gap, which is delimited by two pole surfaces of the magnetic core and into which the flat data carrier can be inserted in order to be tested, 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 a signal source and a plurality of stripline resonators which are simultaneously fed from the signal source, and the stripline resonators are formed in a planar manner with a main extension plane which is plan-parallel to at least one of the pole surfaces of the magnetic core.