Antenna Impedance-Based Apparatus and Method for Detecting a Breach in the Integrity of a Container

• US 20100171614A1
• Filed: 02/22/2005
• Published: 07/08/2010
• Est. Priority Date: 02/22/2005
• Status: Abandoned Application

• Current Assignee: Chubb International Holding Limited
• Original Assignee: Chubb International Holding Limited
• Inventors: Zacchio, Joseph, Oh, Jae-Hyuk, Concho, Julio I.
• Application Number:
  US11/884,820
• Publication Number:
  US 20100171614A1
• Time in Patent Office: Days
• US Class Current: 340/550
• CPC Class Codes: G08B 13/2491 Intrusion detection systems, i.e. where the body of an intruder causes the interference with the electromagnetic field

Abstract

A security breach in the integrity of a container (10), such as a cargo container or a security vault, is detected using an apparatus (12) formed of a transmitter (18) and a processor (20). The transmitter (18) includes an antenna (26) that radiates electromagnetic waves from within the container (10). The processor (20) measures an impedance of the antenna (26) and produces an alarm if the impedance of the antenna (26) strays indicating a security breach in the integrity of the container (10).

Claims

1. An apparatus for detecting a breach in integrity of a container, the apparatus comprising:

a transmitter having an antenna that radiates electromagnetic waves from within the container; and

a processor that measures an impedance of the antenna and determines if the measured impedance of the antenna indicates a breach in the integrity of the container.

2. The apparatus of claim 1 wherein the transmitter further includes a signal generator that generates a signal for transmission to the antenna.

3. The apparatus of claim 2 wherein a frequency of the signal is swept over a band of frequencies.

4. The apparatus of claim 2 wherein the signal is a radio frequency signal.

5. The apparatus of claim 2 wherein the signal is a microwave frequency signal.

6. The apparatus of claim 1 wherein the processor indicates a breach when a difference between the measured impedance of the antenna and a baseline impedance of the antenna exceeds a threshold deviation.

7. The apparatus of claim 1 wherein the processor generates an alarm upon determining that the measured impedance of the antenna indicates a breach in the integrity of the container.

8. The apparatus of claim 1 wherein the container is a cargo container.

9. The apparatus of claim 1 wherein the container is a security vault.

10. A method for detecting a breach in integrity of a container, the method comprising:

radiating electromagnetic waves from an antenna positioned within the container;

monitoring an impedance of the antenna; and

detecting that a breach in the integrity of the container has occurred in response to a change of the impedance caused by a change in a structure or contents of the container.

11. The method of claim 10 continuously implemented.

12. The method of claim 10 periodically implemented.

13. The method of claim 10 wherein detecting that a breach in the integrity of the container has occurred comprises:

detecting whether a difference between the measured impedance of the antenna and a baseline impedance of the antenna exceeds a threshold deviation.

14. The method of claim 10 and further comprising:

producing an alarm upon detection of the occurrence of a breach in the integrity of the container.

15. A method for detecting a breach in integrity of a container, the method comprising:

generating a signal having its frequency swept over a band of frequencies;

for each frequency of the signal, transmitting that signal to an antenna for radiation of electromagnetic waves from within the container and measuring a resultant impedance of the antenna;

determining a breach indicator value based upon the measured impedances of the antenna; and

detecting whether the breach indicator value indicates a breach in the integrity of the container.

16. The method of claim 15 wherein the band of frequencies includes radio frequencies.

17. The method of claim 15 wherein the band of frequencies includes microwave frequencies.

18. The method of claim 15 wherein determining a breach indicator value comprises:

for each frequency of the signal, determining a difference between the measured impedance and a baseline impedance for that frequency; and

determining a breach indicator value as a sum of a square of the differences.

19. The method of claim 15 wherein determining a breach indicator value comprises:

for each frequency of the signal, determining a difference between a reflection coefficient based upon the measured impedance for that frequency and a baseline reflection coefficient for that frequency; and

determining a breach indicator value as a sum of a square of the differences.

20. The method of claim 15 wherein detecting whether the breach indicator value indicates a breach in the integrity of the container comprises:

detecting whether the breach indicator value exceeds a threshold breach indicator value.