Detection of resonant tags by ultra-wideband (UWB) radar

• US 7,719,280 B2
• Filed: 05/17/2007
• Issued: 05/18/2010
• Est. Priority Date: 05/22/2006
• Status: Active Grant

• Current Assignee: IMEC International
• Original Assignee: IMEC International
• Inventors: Borghs, Gustaaf, Lagae, Liesbet
• Primary Examiner(s): Shrivastav; Brij B
• Application Number:
  US11/750,155
• Publication Number:
  US 20080252293A1
• Time in Patent Office: 1,097 Days
• Field of Search: 324300-322, 600407-445, 378/4, 378/15, 378/901, 455/456.1, 455/456.2, 455/133, 342/450
• US Class Current: 324/322
• CPC Class Codes: A61N 1/403 for thermotherapy, e.g. hyperthermia
• CPC Class Codes: G01S 13/0209 Systems with very large relative bandwidth, i.e. larger than 10 %, e.g. baseband, pulse, carrier-free, ultrawideband
• CPC Class Codes: G01S 13/75 using transponders powered from received waves, e.g. using passive transponders , or using passive reflectors
• CPC Class Codes: G01S 13/753 using frequency selective elements, e.g. resonator
• CPC Class Codes: G01S 7/411 Identification of targets based on measurements of radar reflectivity G01S7/415 takes precedence
• CPC Class Codes: H04B 1/7163 using impulse radio

Abstract

A detection system having a receiver for detecting a material having a magnetic resonance response to illumination by pulses of ultra-wideband (UWB) electromagnetic radiation is disclosed. The receiver comprises a detector for detecting the pulses after they have interacted with the material, and a discriminator arranged to identify in the detected pulses the magnetic resonance response of the material. By scanning an item tagged with a tag having a material having a magnetic resonant response, by illuminating the item with UWB pulses and identifying in detected pulses the magnetic resonance response of the material, items can be located, imaged, or activated. The magnetic resonance response of the tag can cause activation of the tag. The tag can have a magnetic resonance response arranged to provide an identifiable magnetic resonance signature such that different tags can be identified and distinguished by their signatures.

Claims

1. A detection system comprising:

a transmitter configured to transmit a series of pulses of ultra-wideband (UWB) electromagnetic radiation; and

at least one receiver configured to receive echo pulses of the series of UWB pulses and to identify a signature in the echo pulses, the signature being indicative of a material exhibiting magnetic resonance induced by the series of pulses.

2. The detection system according to claim 1, wherein the transmitted pulses of UWB electromagnetic radiation have a fractional bandwidth of at least 20% and center frequencies between about 500 MHz and 20 GHz.

3. The detection system according to claim 1, wherein the receiver comprises a correlator circuit to identify the signature.

4. The detection system according to claim 1, wherein the receiver is configured to identify the signature by determining at least one of the following:

a change in pulse shape, a time lag, polarization changes, and a frequency spectrum of the pulse.

5. The detection system according to claim 1, wherein the magnetic resonant material is one of the following:

a ferrimagnetic material, a ferromagnetic material, an antiferromagnetic material, a superparamagnetic material, and a metamaterial showing magnetic resonance within the fractional bandwidth of the transmitted pulses.

6. The detection system according to claim 5, wherein a shape of the magnetic resonant material is one of:

a sphere, an ellipse or ellipsoid, an elongated wire, a closed circular or square ring, a split ring or unclosed ring, a ring with multiple splits, two or more concentric rings.

7. The detections system according to claim 6, wherein a shape of the magnetic resonant material comprises an ensemble of N shapes arranged in periodic or random order.

8. The detection system according to claim 1, wherein the receiver is configured to determine the distance of the magnetic resonant material to the receiver by determining a time-of-arrival.

9. The detection system according to claim 1, wherein the system comprises at least two receivers and the receivers being configured to determine a location of the magnetic resonant material by time-of-arrival and/or angle of arrival.

10. The detection system according to claim 1, wherein the system is configured to determine the relative location of two magnetic resonant materials by determining a time difference of arrival.

11. The detection system according to claim 1, wherein the magnetic resonant material is a part of an electronic identification tag.

12. The detection system according to claim 1, wherein the magnetic resonant material is located in a magnetic field of approximately <

0.3T.

13. The detection system according to claim 1, wherein the transmitted pulses of UWB electromagnetic radiation have a fractional bandwidth of approximately 20% to 200%.

14. A receiver for receiving echoes of a series of pulses of ultra-wideband (UWB) electromagnetic radiation, the receiver comprising:

a detection unit configured to identify a signature in echo pulses of a series of pulses of ultra-wideband electromagnetic radiation, the signature being indicative of reflection from a material exhibiting magnetic resonance induced by the series of pulses.

15. A receiver according to claim 14, wherein the detection unit comprises a correlator circuit for identifying echo pulses from the series of pulses.

16. A receiver for detecting a material having a magnetic resonance response to illumination by pulses of ultra-wideband (UWB) electromagnetic radiation, the receiver comprising:

a detector configured to detect the pulses after they have interacted with the material; and

a discriminator configured to identify in the detected pulses the magnetic resonance response of the material.

17. The receiver according to claim 16, further comprising a signal processor configured to determine one or more of the following:

a distance from the material by determining a time of travel of the detected pulses, successive positions of the material for motion analysis or position tracking, and an orientation of the material.

18. The receiver according to claim 16, further comprising a plurality of receive antennas configured to carry out a spatial correlation to determine positioning in two or three dimensions.

19. The receiver according to claim 16, wherein the discriminator is configured to discriminate between different magnetic resonance responses from an active material, or from multiple materials having different responses.

20. The receiver according to claim 16, further comprising a processor configured to generate an image from scanning of the pulses or scanning of a receiver across the material.

21. A system comprising:

a transmitter of pulses of ultra-wideband (UWB) electromagnetic radiation; and

a receiver configured to detect a material having a magnetic resonance response to illumination by pulses of UWB electromagnetic radiation, the receiver comprising;

a detector configured to detect the pulses after they have interacted with the material,

a discriminator configured to identify in the detected pulses the magnetic resonance response of the material, and

a processor configured to generate an image from scanning of the pulses or scanning of a receiver across the material.

22. The system according to claim 21, further comprising multiple antennas configured to illuminate the material from different angles, the receiver being arranged to distinguish the pulses from the different angles.

23. The system according to claim 22, wherein the system is configured to transmit a beam and scan the beam across the material, the receiver being arranged to determine a location of the material based at least in part on the scanning of the beam.

24. The system according to claim 22, wherein the system is configured to send separate pulses to excite a resonance and to probe the excited resonance, the receiver being arranged to distinguish between the exciting and the probe pulses.

25. The system according to claim 22, wherein the system is configured to scan internal parts of a human or animal body.

26. A method of scanning an item tagged with a tag having a material having a magnetic resonant response, the method comprising:

illuminating the item with pulses of ultra-wideband (UWB) electromagnetic radiation;

detecting the pulses after they have interacted with the material; and

identifying in the detected pulses the magnetic resonance response of the material.

27. The method according to claim 26, wherein the tag is an active tag, and the method further comprises using the pulses to activate the tag.

28. The method according to claim 26, wherein the item is a human or other animal body.

29. A method of activating a tag in an item, the tag having a material having a magnetic resonant response, the method comprising:

illuminating the item with pulses of ultra-wideband (UWB) electromagnetic radiation such that the magnetic resonance response of the tag causes activation of the tag.

30. The method according to claim 29, wherein the tag is activated thermally by magnetic resonance heating of the tag caused by the illumination of the tag by UWB electromagnetic radiation.

31. A resonant tag for being read with ultra-wideband (UWB) radiation comprising:

a material having a magnetic resonance response configured to provide an identifiable magnetic resonance signature response to illumination by pulses of UWB radiation, such that different tags can be identified and distinguished by their signatures.

32. A resonant tag for being read with ultra-wideband (UWB) radiation comprising:

a material having a magnetic resonance response configured to provide a resonance frequency related to at least one parameter that represents a sensor value being probed by pulses of UWB radiation, such that it acts as a wireless sensor.