Interrogator and goods management system adopting the same

• US 20020175804A1
• Filed: 08/31/2001
• Published: 11/28/2002
• Est. Priority Date: 05/22/2001
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Saito, Takeshi
• Granted Patent: US 7,164,380 B2
• Time in Patent Office: Days
• US Class Current: 340/10.1
• CPC Class Codes: G06K 7/10336 the antenna being of the near field type, inductive coil
• CPC Class Codes: G06K 7/10346 the antenna being of the far field type, e.g. HF types or dipoles
• CPC Class Codes: H01Q 1/2216 used in interrogator/reader equipment
• CPC Class Codes: H01Q 21/061 Two dimensional planar arrays
• CPC Class Codes: H01Q 3/24 varying the orientation by switching energy from one active radiating element to another, e.g. for beam switching
• CPC Class Codes: H01Q 9/30 with feed to end of elongated active element, e.g. unipole H01Q9/44 takes precedence

Abstract

The invention provides an interrogator with an antenna that allows information exchanges with multiple transponders in a shorter distance of communication, by securing an intensified and uniform electromagnetic energy concentrated on areas near antenna elements. The interrogator is furnished with a sleeve antenna that includes a monopole conductor of ¼ wavelength (free space wavelength) continuously connected to a core wire of a coaxial cable on one end thereof, and a feed point on the other end, in which the sleeve antenna is grounded at the feed point. The interrogator has a plurality of the transponders arrayed near the antenna, and a plurality of the antennas selected by RF signal selectors. The interrogator antenna of the invention will achieve movable body identification equipment such as a goods management system for identifying multiply arrayed goods, etc.

Claims

1. An interrogator that forms movable body identification equipment together with plural transponders, comprising at least one sleeve antenna as an antenna that executes an information exchange with the plural transponders by a radio communication using the microwave band.

2. An interrogator according to claim 1, wherein a grounded conductive plate is disposed close to the at least one sleeve antenna, on a side opposite to a side on which the transponders related to the at least one sleeve antenna are disposed.

3. An interrogator according to claim 1, wherein, when the at least one sleeve antenna represents plural antennas, the interrogator possesses an RF signal selector that selects either one of the plural sleeve antennas in correspondence with each of the plural antennas.

4. An interrogator according to claim 2, wherein, when the at least one sleeve antenna represents plural antennas, the interrogator possesses an RF signal selector that selects either one of the plural sleeve antennas in correspondence with each of the plural antennas.

5. An interrogator according to claim 3, wherein a switching signal to drive the RF signal selector is created on the basis of a pulse count signal being superposed on an RF signal outputted from the interrogator.

6. An interrogator according to claim 3, further comprising an indicator that operates synchronously with the RF signal selector, in combination with the selector.

7. An interrogator according to claim 3, further comprising a sound source that operates synchronously with the RF signal selector, in combination with the selector.

8. An interrogator according to claim 1, wherein the transponders of a flat rectangular shape are arrayed close to the at least one sleeve antenna.

9. An interrogator according to claim 2, wherein the transponders of a flat rectangular shape are arrayed close to the at least one sleeve antenna.

10. An interrogator according to claim 3, wherein the plural sleeve antennas are divided into plural antenna groups, and an RF signal from the interrogator is supplied in parallel to the plural antenna groups.

11. An interrogator according to claim 3, wherein the plural sleeve antennas are divided into plural antenna groups, and an RF signal from the interrogator is supplied in parallel to the plural antenna groups, through another RF signal selector that selects either one group of the antenna groups.

13. A goods management system according to claim 12, wherein the plural sleeve antennas are divided into plural antenna groups, and an RF signal from the interrogator is supplied in parallel to the plural antenna groups, through another RF signal selector that selects either one group of the antenna groups.

14. A goods management system according to claim 13, further comprising an indicator that operates synchronously with the RF signal selector and another RF signal selector, in combination with the selector and another selector.

15. A goods management system according to claim 13, further comprising a sound source that operates synchronously with the RF signal selector and another RF signal selector, in combination with the selector and another selector.

12. A goods management system comprising:

plural transponders of a flat rectangular shape that are each attached on sides of each of plural goods;

an interrogator that executes an information exchange with the plural transponders by a radio communication using the microwave band;

and a management terminal that controls the plural goods, using information from the interrogator acquired by the information exchange;

wherein the interrogator includes;

plural sleeve antennas for exchanging information with the plural transponders;

a grounded conductive plate disposed close to the plural sleeve antennas, on a side opposite to a side on which the plural transponders related to the plural sleeve antennas are disposed; and

an RF signal selector that selects either one of the plural sleeve antennas, wherein the transponders are arrayed close to the plural sleeve antennas.