Stripline Resonator Sensor for High-Speed Banknote Spin Testing
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Solution Overview
Problem
Existing devices for testing data carriers with spin resonance characteristics, such as banknotes, face challenges in achieving high-speed testing using methods like CW, pulsed, and rapid-scan techniques due to limitations in signal-to-noise ratio and efficiency.
Innovation Solution
A sensor element comprising a magnetic core with an air gap, a stripline resonator, and a modulation device for generating a modulated magnetic field, optimized for planar data carriers, which includes a conductive structure on a planar support with a ground loop and operates in various spatial modes to enhance signal measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional resonators are used for spin resonance measurement, then the measurement can be performed, but the signal-to-noise ratio is dominated by resonator losses and high-frequency radiation, limiting measurement reliability
Solution Approach 1:
A stripline structure is introduced as an intermediary between the spin resonance feature and the measurement system. The stripline acts as a waveguide that channels the electromagnetic signal from the resonant spins to the measurement equipment, reducing direct radiation losses and improving signal-to-noise ratio by confining the electromagnetic field within the stripline structure.
Solution Approach 2:
The patent replaces conventional resonator structures with a stripline-based measurement system. This substitution eliminates the need for traditional resonator cavities and their associated losses, using instead a transmission line structure that guides electromagnetic waves with lower loss and better signal confinement.
2Productivity
If high-speed testing is implemented using CW, pulsed, or rapid-scan techniques, then productivity increases, but measurement precision deteriorates due to reduced signal-to-noise ratio
Solution Approach 1:
The stripline structure enables continuous measurement of spin resonance signals during high-speed transport of data carriers. The waveguide structure maintains signal integrity throughout the measurement process, allowing continuous data acquisition without loss of signal-to-noise ratio even at high testing speeds.
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-speed, reliable measurement of spin resonance features with improved signal-to-noise ratio, allowing for efficient authentication of planar data carriers like banknotes, even in the presence of external interference.
Implementation Method 1
A sensor element (30) comprises a magnetic core (34) with an air gap into which a data carrier (10) can be inserted for testing, and a resonator (32) for exciting the spin resonance feature of the data carrier (10) to be tested
Implementation Method 2
Spin resonance features are generally based on the resonant energy absorption of a spin ensemble in an external magnetic field. By applying an alternating magnetic field of suitable strength, oriented perpendicular to the external magnetic field (referred to as the polarization field), resonant transitions between the energy levels can be induced.
Implementation Method 3
Some spin resonance effects can also be measured using a pulsed technique, in which the population states are manipulated by resonant single pulses or pulse sequences of the high-frequency signal.
Data Source
Figure 1~2
Figure 3(a)~4(b)
Figure 5~6(b)
AI summary
The invention relates to a sensor element (30) for testing a flat data carrier (10), in particular a banknote, that has a spin resonance feature (12). The sensor element contains a magnetic core (34) having an air gap, into which the flat data carrier (10) can be inserted for testing, an element for generating a static magnetic flux in the air gap, and a resonator (32) for exciting the spin resonance feature of the data carrier to be tested. According to the invention, it is provided that the resonator is formed by a stripline resonator (40) which is arranged in the air gap of the magnetic core and comprises a flat carrier (42) having an upper side (44-O) and a conducting structure (46) which is arranged on the upper side (44-O) of the carrier with a characteristic length l.