System and method for multiple reading interface with a simple RFID antenna

• US 8,816,824 B2
• Filed: 07/11/2011
• Issued: 08/26/2014
• Est. Priority Date: 08/27/2010
• Status: Active Grant

• Current Assignee: Psion PLC (Motorola Solutions, Inc.)
• Original Assignee: Psion PLC (Motorola Solutions, Inc.)
• Inventors: Barry, Fabien, Collombon, Jan-Manuel, Fornier, Nicolas
• Primary Examiner(s): Lim, Steven
• Assistant Examiner(s): Knox, Kaleria
• Application Number:
  US13/180,012
• Publication Number:
  US 20120050017A1
• Time in Patent Office: 1,142 Days
• Field of Search: 340/571, 340/505, 340/572.7, 340/10.1, 342/146, 343/742, 343/702, 343/842, 343/841, 244/50, 235/385, 307/104, 324/322, 333/113, 600/410
• US Class Current: 340/10.1
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10336 the antenna being of the near field type, inductive coil
• 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
• CPC Class Codes: H01Q 1/2216 used in interrogator/reader equipment
• CPC Class Codes: H01Q 21/28 Combinations of substantially independent non-interacting antenna units or systems multiple beam H01Q25/00
• 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 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop

Abstract

A multi-field antenna able to receive a signal over one field selected from a plurality of different fields of the antenna includes an interface to connect the antenna to a signal processing device, such as an RFID reader, to receive and process the signal. The antenna includes a first magnetic loop configured to be tuned by a first tuner to provide a first volume field for reading data; a second magnetic loop configured to be tuned by a second tuner to provide a second volume field for reading data, the second volume field being smaller than the first volume field; and a switch to configure the first tuner and the second tuner to select the one field from the plurality of fields. The multi-field antenna can have a wide volume field selected to detect items within a large area and then the multi-field antenna can be switched to select a smaller volume field to detect items within a substantially smaller area. In a preferred embodiment, the multi-field antenna further includes; a first metallic element configured to cover at least a portion of the second magnetic loop, the first metallic element comprising a slot extending from one end of the first metallic element to a point proximal an opposite end of the first metallic element. Also preferably, the multi-field antenna can also create a point volume field, smaller than the second volume field, to localize detected objects within a still smaller area.

Claims

1. A multi-field antenna configured to receive a signal over one field selected from a plurality of different fields of the antenna, the multi-field antenna comprising:

a first magnetic loop;

a first tuner to tune the first magnetic loop to provide a first volume field for reading data;

a second magnetic loop;

a second tuner to tune the second magnetic loop to provide a second volume field for reading data, the second volume field being smaller than the first volume field;

a first metallic element configured to cover at least a portion of the second magnetic loop, the first metallic element creating a mask for the first magnetic loop from the second magnetic loop, the first metallic element comprising a slot extending along a length of the first metallic element from one end of the first metallic element to a point proximal an opposite end of the first metallic element, wherein the field area of the second volume field is defined, in part, based on the dimension of the slot;

a switch to configure the first tuner and the second tuner to select the one field of the plurality of fields; and

an interface to connect the multi-field antenna with a signal processing device operable to receive and process the signal.

2. The multi-field antenna of claim 1, wherein the slot further comprises an aperture at the one end of the first metallic element and the multi-field antenna further comprises a ferrite nub coupled to the second magnetic loop at an end adjacent the aperture, the ferrite nub configured to provide a third volume field, the third volume field being smaller than the second volume field.

3. The multi-field antenna of claim 2, further comprising a second metallic element configured to direct the third field away from the second magnetic loop.

4. The multi-field antenna of claim 1, wherein the signal processing device comprises an RFID reader.

5. The multi-field antenna of claim 4, wherein the signal processing device further comprises a mobile computer.

6. The multi-field antenna of claim 5, wherein the switch is operable by software executing on the mobile computer.

7. The multi-field antenna of claim 1, wherein the first magnetic loop is substantially rectangular in shape.

8. The multi-field antenna of claim 1, wherein at least one of the combination of the first magnetic loop and the second magnetic loop, the first magnetic loop and the first metallic element or the first magnetic loop are in the same plane.

9. The multi-field antenna of claim 1, wherein the second magnetic loop and the first metallic element are in different planes.

10. The multi-field antenna of claim 1, wherein, when a first field is selected, the first magnetic loop is activated and the second magnetic loop is deactivated.

11. The multi-field antenna of claim 10, wherein the second magnetic loop is deactivated by at least one of providing the second magnetic loop with an open circuit or connecting a load across the second magnetic loop.

12. The multi-field antenna of claim 1, wherein the switch is provided on the multi-field antenna.

13. The multi-field antenna of claim 1, wherein when a second field is selected, the second magnetic loop is activated and the first magnetic loop is deactivated.

14. The multi-field antenna of claim 13, wherein the first magnetic loop is deactivated by at least one of providing the first magnetic loop with an open circuit or connecting a load across the first magnetic loop.

16. The mobile computer of claim 14, wherein the slot further comprises an aperture at the one end of the first metallic element and the multi-field antenna further comprises a ferrite nub coupled to the second magnetic loop at an end adjacent the aperture, the ferrite nub configured to provide a third volume field, the third volume field being smaller than the second volume field.

15. A mobile computer device comprising:

an RFID reader;

memory having stored instructions;

a microprocessor configured to implement the stored instructions for receiving and processing a signal from the RFID reader; and

a multi-field antenna connected to the RFID reader, the multi-field antenna operable to receive a signal over one field selected from a plurality of different fields of the multi-field antenna and comprising;

a first magnetic loop;

a first tuner to tune the first magnetic loop to provide a first volume field for reading data from RFID tags;

a second magnetic loop;

a second tuner to tune the second magnetic loop to provide a second volume field for reading data from RFID tags, the second volume field being smaller than the first volume field;

a first metallic element configured to cover at least a portion of the second magnetic loop, the first metallic element creating a mask for the first magnetic loop from the second magnetic loop, the first metallic element comprising a slot extending along a length of the first metallic element from one end of the first metallic element to a point proximal an opposite end of the first metallic element, wherein the field area of the second volume field is defined, in part, based on the dimension of the slot; and

a switch to configure the first tuner and the second tuner to select the one field from the plurality of fields.

17. The mobile computer of claim 15, wherein the switch is controlled by the microprocessor.

18. The mobile computer of claim 15, wherein the memory further includes instructions for automatically identifying a position of each of a plurality of items stored in an array, wherein each of the plurality of items are tagged with a device configured to store and transmit a unique identifier after rows columns of the array have been scanned using the multi-field antenna.