Electronic tag authentication device and communication adjustment method with electronic tag

• US 20060022884A1
• Filed: 11/23/2004
• Published: 02/02/2006
• Est. Priority Date: 07/30/2004
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Kai, Manabu, Hayashi, Hiroyuki, Maniwa, Toru, Andrenko, Andrey
• Granted Patent: US 7,388,499 B2
• Time in Patent Office: Days
• US Class Current: 343/757
• CPC Class Codes: H01Q 3/2623 composed of two antennas
• CPC Class Codes: H01Q 3/28 varying the amplitude
• CPC Class Codes: H01Q 3/40 with phasing matrix

Abstract

The electronic tag authentication device of the present invention authenticates the contents of an electronic tag attached to goods. The electronic tag authentication device comprises an antenna directivity change unit for changing the directivity of an antenna for transmitting/receiving electrical waves in order to authenticate the contents of the electronic tag.

Claims

1. An electronic tag authentication device, comprising

an antenna directivity change unit for changing the directivity of an antenna for transmitting/receiving electrical waves in order to authenticate the contents of an electronic tag attached to a goods.

2. The electronic tag authentication device according to claim 1, wherein

said antenna is composed of a plurality of element antennas, and

said antenna directivity change unit comprises in accordance with the plurality of element antennas

a plurality of power feeding units capable of adjusting the amplitude and phase of a power feeding signal supplied to each element antenna.

3. The electronic tag authentication device according to claim 2, wherein

the power feeding unit with desired directivity is selected from said plurality of power feeding units whose influence on antenna directivity is known, by switching said plurality of power feeding units.

4. The electronic tag authentication device according to claim 1, wherein

said antenna is composed of a plurality of element antennas, and

said antenna directivity change unit comprises

a plurality of power feeding units capable of adjusting the amplitude and phase of a power feeding signal supplied to each element antenna;

and

a switching unit for changing the connection state between the plurality of power feeding units and the plurality of element antennas.

5. The electronic tag authentication device according to claim 4, wherein

said power feeding unit comprises a phase shifter electrically controlled externally and a power divider.

6. The electronic tag authentication device according to claim 4, wherein

said power feeding unit is composed of T-character type power feeding network.

7. The electronic tag authentication device according to claim 4, wherein

said power feeding unit is composed of hybrid type power feeding network.

8. An adjustment method of communication with an electronic tag attached to goods, comprising:

disposing goods whose tag content is known, inside the boundary of the reading range of an electronic tag authentication device in order to conduct the communication; and

changing the directivity of the antenna of the relevant authentication device in such a way that the known tag contents can be correctly read during the operation of another electronic tag authentication device whose reading target is a range adjacent to said reading range.