ANTENNA APPARATUS FOR DETERMINING THE POSITION OF A RADIO-FREQUENCY TRANSPONDER

• US 20130009820A1
• Filed: 07/08/2011
• Published: 01/10/2013
• Est. Priority Date: 07/08/2011
• Status: Active Grant

• Current Assignee: Psion PLC (Motorola Solutions, Inc.)
• Original Assignee: Psion PLC (Motorola Solutions, Inc.)
• Inventors: Bonnefoy, Pierre, Limongi, Benjamin
• Granted Patent: US 9,151,819 B2
• Time in Patent Office: Days
• US Class Current: 342/368
• CPC Class Codes: G01S 3/40 adjusting orientation of a single directivity characteristic to produce maximum or minimum signal, e.g. rotatable loop antenna or equivalent goniometer system
• CPC Class Codes: H01Q 1/2208 associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems methods or arrangements for sensing record carriers, e.g. for reading patterns G06K7/00; record carrier for use with machines and with at least a part designed to carry digital markings G06K19/00
• CPC Class Codes: H01Q 21/00 Antenna arrays or systems arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system H01Q3/00

Abstract

An antenna apparatus for determining the position of a radio-frequency transponder is provided, comprising a phased array of antennas enabled to transmit and receive power at a given frequency for communicating with a radio frequency (RF) transponder, the phased array being movable; and a phase shifter for providing a phase shift to at least one antenna of the phased array to provide a minima in a main radiated lobe of the phased array, such that when the phased array is moved from a first position, for detecting the RF transponder via the main radiated lobe, to a second position, where a signal from the RF transponder is minimized, a position of the RF transponder determined to be along an axis of the minima in the second position.

Claims

1. An antenna apparatus comprising:

a phased array of antennas enabled to transmit and receive power at a given frequency for communicating with a radio frequency (RF) transponder, the phased array being movable; and

,

a phase shifter for providing a phase shift to at least one antenna of the phased array to provide a minima in a main radiated lobe of the phased array, such that when the phased array is moved from a first position, for detecting the RF transponder via the main radiated lobe, to a second position, where a signal from the RF transponder is minimized, a position of the RF transponder determined to be along an axis of the minima in the second position.

2. The antenna apparatus of claim 1, wherein the minima comprises a null and no response is received from the RF transponder when the RF transponder is located along the axis of the minima in the second position.

3. The antenna apparatus of claim 1, wherein the phase shift is approximately 180°

.

4. The antenna apparatus of claim 3, wherein the phased array comprises a first pair of antennas, wherein the centers thereof are separated by approximately half of a wavelength associated with the given frequency.

5. The antenna apparatus of claim 3, wherein the phased array further comprises a second pair of antennas laterally displaced from the first pair, one antenna of the second pair enabled to be out of phase with the remaining antenna of the second pair providing a second minima in the main radiated lobe perpendicular to the minima such that the RF transponder can be located in at least two spatial dimensions.

6. The antenna apparatus of claim 1, further comprising:

at least at least one RF transceiver for powering the phased array.

7. The antenna apparatus of claim 6, wherein the at least one RF transceiver is common to all antennas of the phased array, and further comprising a power splitter for splitting power from the at least one RF transceiver to all the antennas of the phased array.

8. The antenna apparatus of claim 1, further comprising a processor for determining when the signal from the RF transponder is minimized, and in response providing an indication of the location of the RF transponder.

9. The antenna apparatus of claim 8, wherein providing the indication of the location of the RF transponder comprises at least one of:

rendering visual indicator at a display to indicate the location;

controlling a speaker to provide an aural indicator to indicate the location;

controlling a light to indicate the location;

controlling a haptic device to indicate the location; and

,

controlling a laser device to indicate the location.

10. The antennas apparatus of claim 1, wherein the phase shifter is configured to be enabled and disabled such that the minima can be turned on and off, and such that the RF transponder can be detected in the first position with the phase shifter disabled and the minima removed, and the position of the RF transponder determined in the second position with the phase shifter enabled and the minima turned on.

11. The antenna apparatus of claim 1, wherein, for detecting the RF transponder in the first position, a given antenna of the phased array is enabled to be on while remaining antennas are enabled to be off in the first position, thereby turning the minima off, and in the second position, the remaining antennas are further enabled to be on, with the at least one antenna phase shifted, thereby turning the minima on.

12. The antenna apparatus of claim 1, further comprising a handheld device for providing data received in the signal from the RF transponder and providing an indication of the position of the RF transponder at a display, the phased array integrated with the handheld device.

13. The antenna apparatus of claim 1, where the given frequency is in at least one of a range of 300 MHz and 100 GHz, and a range of 800 MHz to 950 MHz.

14. A method comprising:

detecting an RF transponder via a main radiated lobe of a phased array of antennas in a first position, the phased array enabled to transmit and receive power at a given UHF (ultra high frequency) frequency for communicating with the RFID (radio frequency identification) tag, the phased array being moveable; and

,

determining a position of the RF transponder when the phased array is moved to a second position where a signal from the RF transponder is minimized, at least one antenna of the phased array phase shifted using a phase shifter to provide a minima in the main radiated lobe, the position of the RF transponder determined to be along an axis of the minima in the second position.

15. The method of claim 14, further comprising providing an indication of the position of the RF transponder.

16. The method of claim 15, wherein providing the indication of the location of the RF transponder comprises at least one of:

rendering visual indicator at a display to indicate the location;

controlling a speaker to provide an aural indicator to indicate the location;

controlling a light to indicate the location;

controlling a haptic device to indicate the location; and

,

controlling a laser device to indicate the location.

17. The method of claim 14, wherein the phase shifter is configured to be enabled and disabled such that the minima can be turned on and off, the method further comprising detecting the RF transponder in the first position with the phase shifter disabled and the minima removed, and determining the position of the RF transponder in the second position with the phase shifter enabled and the minima turned on.

18. The method of claim 14, wherein, for detecting the RF transponder in the first position, a given antenna of the phased array is enabled to be on while remaining antennas are enabled to be off in the first position, thereby turning the minima off, and in the second position, the remaining antennas are further enabled to be on, with the at least one antenna phase shifted, thereby turning the minima on.

19. A computing device comprising:

a phased array of antennas enabled to transmit and receive power at a given frequency for communicating with a radio frequency (RF) based-tracking device, the phased array being movable;

a phase shifter for providing a phase shift to at least one antenna of the phased array to provide a minima in a main radiated lobe of the phased array; and

a processing unit enabled to;

detect the RF transponder via the main radiated lobe of the phased array of antennas in a first position; and

determine a position of the RF transponder when the phased array is moved to a second position where a signal from the RF transponder is minimized, the position of the RF transponder determined to be along an axis of the minima in the second position.

20. A computer program product, comprising a computer usable medium having a computer readable program code adapted to be executed to implement a method comprising:

a phased array of antennas enabled to transmit and receive power at a given frequency for communicating with a radio frequency (RF) transponder, the phased array being movable; and

,

a phase shifter for providing a phase shift to at least one antenna of the phased array to provide a minima in a main radiated lobe of the phased array, such that when the phased array is moved from a first position, for detecting the RF transponder via the main radiated lobe, to a second position, where a signal from the RF transponder is minimized, a position of the RF transponder determined to be along an axis of the minima in the second position.