Sensor element, test device and method for testing data carriers having a spin resonance feature

Patent metadata

Field	Value
Publication number	US-12573254-B2
Application number	US-202218552579-A
Country	US
Kind code	B2
Filing date	Mar 22, 2022
Priority date	Mar 26, 2021
Publication date	Mar 10, 2026
Grant date	Mar 10, 2026

Abstract

A sensor element for testing a flat data carrier, in particular a banknote, has a spin resonance feature. The sensor element contains a magnetic core having an air gap, into which the flat data carrier can be inserted for testing, an element for generating a static magnetic flux in the air gap, and a resonator for exciting the spin resonance feature of the data carrier to be tested. The resonator is formed by a microstrip line resonator which is arranged in the air gap of the magnetic core and comprises a flat carrier having an upper side and a conducting structure which is arranged on the upper side of the carrier with a characteristic length.

First claim

The invention claimed is:

1 . A sensor element for testing a flat data carrier, comprising:
a magnetic core having an air gap into which the flat data carrier is insertable for the test, an element for generating a static magnetic flux in the air gap, and a resonator for exciting a spin resonance feature of the data carrier under test, wherein the resonator is formed by a microstrip line resonator which is arranged in the air gap of the magnetic core and which has a flat carrier with an upper side and an opposing lower side, wherein a conducting structure having a characteristic length l is arranged on the upper side, wherein the microstrip line resonator is designed for excitation of spin resonance signals having a frequency between 1 GHz and 100 GHz.

2 . The sensor element according to claim 1 , wherein the carrier has a ground area arranged on the lower side.

3 . The sensor element according to claim 1 , wherein the microstrip line resonator forms a λ/4 fundamental mode, a λ2 fundamental mode or a λ fundamental mode.

4 . The sensor element according to claim 1 , wherein the microstrip line resonator as a conducting structure comprises a rectangular structure, an annular structure having a circular or elliptical outer contour, a disc-shaped structure, a ring-sector structure having round or elliptical outer edges, or a structure having a triangular or polygonal shape.

5 . The sensor element according to claim 1 , wherein the microstrip line resonator with its characteristic length l is designed and configured for testing the spin resonance feature of the data carrier in a higher-order spatial mode of an excitation field.

6 . The sensor element according to claim 1 , wherein the microstrip line resonator has a quality Q between 50 and 400.

7 . The sensor element according to claim 1 , wherein the microstrip line resonator is arranged in the air gap parallel to and distanced from a metallized shielding element in order to reduce radiation losses of the resonator.

8 . The sensor element according to claim 1 , wherein the sensor element is designed and configured for testing an electron spin resonance feature or a ferromagnetic or ferrimagnetic resonance feature.

9 . A test device for testing flat data carriers having a sensor element according to claim 1 and having a transport device which inserts the flat data carriers under test along a transport path into the air gap of the magnetic core or feeds them through the air gap of the magnetic core.

10 . The test device according to claim 9 , wherein the transport device is designed and configured for a fast-running transport of the flat data carriers under test along the transport path.

11 . The test device according to claim 9 , wherein the transport device is designed and configured to feed the flat data carriers under test along a transport path at a short distance above the upper side of the microstrip line resonator.

12 . The test device according to claim 9 , wherein the sensor element is equipped with a shielding element, and the transport device is designed and configured to feed the flat data carriers under test along the transport path in a slot between the microstrip line resonator and the shielding element.

13 . The test device according to claim 9 , wherein the test device has a signal source for a pulsed activation of the microstrip line resonator and/or for an operation of the microstrip line resonator using a rapid-scan method and/or using a CW method.

14 . The sensor element according to claim 1 , wherein the microstrip line resonator with its characteristic length l is designed and configured for testing the spin resonance feature of the data carrier in a second-order or third-order mode of an excitation field.

15 . A method for testing a flat data carrier having a spin resonance feature by means of a sensor element, in which the following steps are carried out:
providing the flat data carrier; feeding the flat data carrier into an air gap of a magnetic core of the sensor element; exciting the spin resonance feature of the flat data carrier by means of a microstrip line resonator of the sensor element arranged in the air gap of the magnetic core; capturing a measurement signal which is characteristic of the spin resonance feature by means of the microstrip line resonator; and testing the flat data carrier by means of the captured measurement signal, wherein the microstrip line resonator is designed for excitation of spin resonance signals having a frequency between 1 GHz and 100 GHz.

Assignees

• Giesecke & Devrient Currency Technology Gmbh

Inventors

• Huber Stephan

Classifications

• G01R33/3456

  Stripline resonators · CPC title

• G01N24/08

  by using nuclear magnetic resonance (G01N24/12 takes precedence) · CPC title

• G01R33/307

  specially adapted for moving the sample relative to the MR system, e.g. spinning mechanisms, flow cells or means for positioning the sample inside a spectrometer · CPC title

• G01R33/60

  using electron paramagnetic resonance (G01R33/24, G01R33/62 take precedence) · CPC title

• G01N24/10

  by using electron paramagnetic resonance (G01N24/12 takes precedence) · CPC title