DIRECTIONAL ANTENNA FOR RFID TAG FINDER

• US 20150084744A1
• Filed: 09/23/2014
• Published: 03/26/2015
• Est. Priority Date: 09/23/2013
• Status: Active Application

• Current Assignee: Hand Held Products Incorporated (Honeywell International Inc.)
• Original Assignee: Hand Held Products Incorporated (Honeywell International Inc.)
• Inventors: HAVENS, William H.
• Granted Patent: US 10,289,877 B2
• Time in Patent Office: Days
• US Class Current: 340/10.3
• CPC Class Codes: G06K 7/10128 the step consisting of detection of the presence of one or more record carriers in the vicinity of the interrogation device
• CPC Class Codes: G06K 7/10356 using a plurality of antennas, e.g. configurations including means to resolve interference between the plurality of antennas
• CPC Class Codes: G06K 7/10386 the interrogation device being of the portable or hand-handheld type, e.g. incorporated in ubiquitous hand-held devices such as PDA or mobile phone, or in the form of a portable dedicated RFID reader

Abstract

A system may include a mobile device comprising an antenna system. The antenna system may include a first antenna to determine a presence of a transponder within an area and a second antenna comprising a directional radiation pattern and that is configured to sweep the area to determine a direction of the transponder. The first antenna may be separate from the second antenna.

Claims

1. A method comprising:

activating a first antenna,

determining, by the first antenna, the general presence of a transponder in an area based on a signal received at the first antenna from the transponder;

activating a second antenna designed to have a null or minimum in a first direction and a radiation pattern in all directions other than the first direction; and

identifying, by the second antenna, a location of the transponder within the area in response to a lack of response to the second antenna when the null or minimum is directed toward the transponder.

2. The method of claim 1, wherein the identifying, using the second antenna, the transponder'"'"'s location comprises sweeping the second antenna about an axis.

3. The method of claim 1, wherein the first antenna comprises an omnidirectional antenna configured to have a radiation pattern in all directions.

4. The method of claim 3, wherein the first antenna determines the presence of a transponder in the area prior to the identifying the transponder location'"'"'s within the area.

5. The method of claim 3, wherein the omnidirectional antenna powers the transponder while the second antenna determines the location of the transponder within the area.

6. The method of claim 1, wherein the particular transponder'"'"'s location is determined by identifying an angular resolution of the transponder relative to the second antenna.

7. An apparatus comprising:

a mobile device comprising an antenna system;

wherein the antenna system comprises;

a first antenna to determine a presence of a transponder within an area; and

a second antenna comprising a directional radiation pattern and that is configured to sweep the area to determine a direction of the transponder, wherein the first antenna is separate from the second antenna.

8. The apparatus of claim 7, wherein the first antenna comprises an antenna having an omnidirectional radiation pattern so as to determine whether the transponder is within the area in any direction.

9. The apparatus of claim 7, wherein at least one transponder is a passive transponder, and wherein the first antenna transmits electromagnetic power to power the at least one transponder.

10. The apparatus of claim 7, wherein the second antenna is active while the first antenna is deactivated.

11. The apparatus of claim 7, wherein the second antenna comprises a nulling antenna comprising a null pattern in one direction.

12. The apparatus of claim 7, wherein the second antenna is configured to continuously sweep about an axis, and, while the second antenna is continuously sweeping, the second antenna sends interrogation signals and record data regarding any transponders responding to any of the interrogation signals.

13. The apparatus of claim 7, further comprising a third antenna that is perpendicular to the second antenna and which sweeps about an axis that is perpendicular to a sweeping axis of the second antenna.

14. The apparatus of claim 7, wherein the first antenna comprises at least one of a horn antenna, a patch antenna, or a metamaterial antenna.

15. The apparatus of claim 7, wherein the first and second antennas are active simultaneously.

16. The apparatus of claim 7, wherein the directional pattern of the first antenna only receives response signals from the transponder when the transponder is encompassed by the directional radiation pattern.

17. A system comprising:

a RFID reader comprising a nulling antenna;

wherein the nulling antenna outputs a null or minimum extending only in one direction so that when the null is directed toward a transponder, the RFID reader is prevented from receiving signals from the transponder, and

wherein the nulling antenna continuously sweeps about an axis to determine;

(1) the presence based on receipt of the signal when a maximum of the antenna is directed toward the transponder and (2) a direction of the transponder based on a lack of signal from the transponder when the null or minimum is pointed toward the transponder.

18. The apparatus of claim 17, wherein the nulling antenna has a radiation pattern which extends in all directions except for the direction of the null or minimum so that the null or minimum sweeps about the axis.

19. The apparatus of claim 17, wherein the nulling antenna is configured to receive signals from the transponder when the transponder is within a range of the nulling antenna and is directionally located outside of the null or minimum.

20. The apparatus of claim 17, wherein the RFID reader further comprises an omnidirectional antenna that is active concurrently with the null or minimum and which is configured to determine the presence of the at least one transponder while the nulling antenna determines the location of the at least one transponder.