SELF-STEERING RFID TAGS

• US 20170200029A1
• Filed: 12/31/2015
• Published: 07/13/2017
• Est. Priority Date: 12/31/2015
• Status: Active Grant

• Current Assignee: Intermec Inc (Honeywell International Inc.)
• Original Assignee: Intermec Inc (Honeywell International Inc.)
• Inventors: NIKITIN, Pavel, Kelly, Stephen J.
• Granted Patent: US 10,503,937 B2
• Time in Patent Office: Days
• CPC Class Codes: G06K 19/07773 Antenna details antennas for wireless devices, e.g. RFID tags, in general H01Q1/22
• CPC Class Codes: G06K 7/10099 the directional field being used for pinpointing the location of the record carrier, e.g. for finding or locating an RFID tag amongst a plurality of RFID tags, each RFID tag being associated with an object, e.g. for physically locating the RFID tagged object in a warehouse
• CPC Class Codes: G06K 7/10168 the powering being adversely affected by environmental influences, e.g. unwanted energy loss in the interrogation signal due to metallic or capacitive objects in the proximity of the interrogation device or in the proximity of the interrogated record carrier
• CPC Class Codes: G06K 7/10405 the interrogation device including an arrangement for sensing environmental parameters, such as a temperature or acceleration sensor, e.g. used as an on/off trigger or as a warning means
• CPC Class Codes: H01Q 1/1257 using the received signal strength
• CPC Class Codes: H01Q 1/2225 used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 19/106 using two or more intersecting plane surfaces, e.g. corner reflector antennas
• CPC Class Codes: H01Q 19/30 the primary active element being centre-fed and substantially straight, e.g. Yagi antenna
• CPC Class Codes: H01Q 21/26 Turnstile or like antennas comprising arrangements of three or more elongated elements disposed radially and symmetrically in a horizontal plane about a common centre

Abstract

A passive, self-steering antenna device is provided along with methods pertaining to operations and controls of the antenna device. The antenna device can include a main antenna for receiving an unmodulated wireless signal, a power harvester configured to obtain power from the unmodulated wireless signal, a main circuit disposed in a central region of the antenna device, and a plurality of peripheral distributed antenna elements configured to modify the radiation pattern of the antenna device. The antenna device can be configured to operate automatically device without needing control information in response to receiving a message from another antenna. Related methods include operations and controls for such an antenna device including automatically performing actions to enhance communications with another antenna device by selecting and activating a subset of the peripheral antenna elements to create a radiation pattern.

Claims

1. A passive antenna device comprising:

a first main antenna element configured to receive an unmodulated wireless signal;

a power harvester configured to obtain power from the unmodulated wireless signal;

a plurality of distributed antenna elements;

a main switch coupled to the power harvester and powered by the obtained power, the main switch configured to place the passive antenna device in an active mode;

a main circuit powered by the obtained power while in the active mode; and

a control unit configured to select a combination of the plurality of distributed antenna elements to provide a non-symmetric radiation pattern for the antenna device while responding to an RFID reader.

2. The antenna device of claim 1, wherein the antenna device is configured to perform actions comprising:

receiving a first wireless signal from a RFID reader;

selecting a first combination of the plurality of distributed antenna elements to activate to provide a non-symmetric radiation pattern while responding to the first wireless signal;

activating the first combination of the plurality of distributed antenna elements; and

sending a first response having a first signal strength to the RFID reader.

3. The antenna device of claim 2, wherein the antenna device is configured to perform further actions comprising:

selecting a second combination of the plurality of the distributed antenna devices for activation that is different than the first combination;

activating the second combination of the plurality of distributed antenna elements; and

sending a second response having a second signal strength to the RFID reader.

4. The antenna device of claim 3, wherein the antenna device is configured to perform further actions comprising:

if the second signal strength is stronger than the first signal strength, saving the second combination of the plurality of distributed antenna devices; and

if the second signal strength is not stronger than the first signal strength;

selecting a third combination of the plurality of the distributed antenna devices for activation;

activating the third combination of the plurality of distributed antenna elements; and

sending a second response having a second signal strength to the RFID reader.

5. The antenna device of claim 1,

wherein the plurality of distributed antenna elements includes a first distributed antenna element and a second distributed antenna element spaced apart from the first distributed antenna element, and

the antenna device further comprises a first distributed switch corresponding with the first distributed antenna element and a second distributed switch corresponding with the second distributed antenna element.

6. The antenna device of claim 5, wherein the first distributed antenna element includes a first reflector dipole, the second distributed antenna element includes a second reflector dipole, and the first and second distributed switches activate the respective first and second distributed dipoles during activation of the combination including the first and second reflector dipole.

7. The antenna device of claim 5, further comprising a second main antenna element disposed proximate the first main antenna at a central region of the antenna device and rotated with respect to the first main antenna element to have a different angular orientation;

wherein the plurality of distributed antenna elements includes a third distributed antenna element and a fourth distributed antenna element spaced apart from the third distributed antenna element;

the antenna device further comprises a third distributed switch corresponding with the third distributed antenna element and a fourth distributed switch corresponding with the fourth distributed antenna element.

wherein the third distributed antenna element includes a third reflector dipole, the fourth distributed antenna element includes a fourth reflector dipole, and the third and fourth distributed switches activate the respective third and fourth distributed dipoles during activation of the combination including the third and fourth reflector dipole.

8. The antenna device of claim 7, wherein:

the main circuit is disposed between each of the first and second distributed antenna elements and the third and fourth distributed antenna elements,

the main circuit is generally centrally located within a central region of the antenna device and the plurality of distributed antenna elements are generally disposed along perimeter regions of the antenna device; and

any combinations of the distributed, perimeter antenna elements can be activated and controlled to provide an enhanced radiation pattern directed toward an RFID reader.

9. The antenna device of claim 1, wherein the plurality of distributed antenna elements includes a plurality of parasitic antenna devices, each parasitic antenna device comprising:

a parasitic element;

a driven element;

a power harvester configured to obtain power from the unmodulated wireless signal; and

a control module coupled with the parasitic element and the driven element and powered by the power harvester,

wherein the control module is configured to communicate with the control unit of the antenna device to selectively activate the parasitic antenna device and drive the driven element to provide a radiation pattern.

10. The antenna device of claim 9, wherein the plurality of distributed antenna elements includes:

a first parasitic antenna element; and

a second parasitic antenna element spaced apart from the first parasitic antenna element;

wherein the main circuit is disposed between the first and second parasitic antenna elements.

11. The antenna device of claim 8, further comprising a second main antenna element disposed proximate the first main antenna at a central region of the antenna device and rotated with respect to the first main antenna element to have a different angular orientation;

wherein the plurality of distributed antenna elements includes a third parasitic antenna element and a fourth parasitic antenna element spaced apart from the third parasitic antenna element;

the antenna device further comprises a third control module corresponding with the third parasitic antenna element and a fourth control module corresponding with the fourth parasitic antenna element.

wherein the third distributed antenna element includes a third reflector dipole, the fourth distributed antenna element includes a fourth reflector dipole, and the third and fourth distributed switches activate the respective third and fourth distributed dipoles during activation of the combination including the third and fourth reflector dipole.

12. A passive, self-steering RFID tag comprising:

a first main antenna disposed in a central region of the tag;

a second main antenna configured to receive an unmodulated wireless signal for powering the device;

a power harvester configured to obtain power from the unmodulated wireless signal;

a plurality of peripheral distributed antenna elements configured to direct a radiation pattern of the RFID tag;

a main switch coupled to the power harvester and configured to activate selectively the passive RFID tag;

a main circuit disposed in the central region and powered by the obtained power while in the active mode; and

a control unit configured to automatically operate responsive to receiving input from a RFID reader and without receiving control information to identify a combination of the plurality of the peripheral distributed antenna elements providing a non-symmetric radiation pattern toward the RFID for enhanced communications.

13. The RFID tag of claim 12, wherein the second main antenna is disposed proximate the first main antenna at a central region of the RFID tag and is rotated with respect to the first main antenna element to have a different angular orientation.

14. A method for enhancing communications with another antenna device with a radiation pattern, the method comprising:

receiving an unmodulated wireless signal;

harvesting power from the unmodulated wireless signal to activate the antenna device and provide power for its operations;

receiving a signal having a first signal strength from another antenna device;

automatically and without receiving control information, selecting a first combination of distributed antenna elements disposed about a peripheral region of the antenna device for forming a radiation pattern to enhance communications with the other antenna device;

activating the first combination of the distributed antenna elements;

comparing the first signal strength with a second signal strength for communicating with the other antenna device based on the first combination of distributed antenna elements;

if the second signal strength is stronger, set the first combination of distributed elements as the combination for communications with the RFID reader, and if not, selecting a second combination of the distributed antenna elements; and

activating the second combination of the distributed antenna elements.

15. The method of claim 14, wherein the distributed antenna elements include a first set of distributed antenna elements generally aligned in a first linear direction and a second set of distributed antenna elements generally aligned in a second linear direction oriented ninety degrees or more from the first linear direction, wherein selecting the first combination of distributed antenna elements includes selecting one or more pairs aligned in the first linear direction without selecting pairs aligned in the second linear direction.

16. The method of claim 15, wherein selecting the second combination of distributed antenna elements includes selecting one or more pairs aligned in the first linear direction and one or more pairs aligned in the second linear direction.

17. The method of claim 15, wherein the first set of distributed antenna elements generally aligned in a first linear direction are associated with first data for communicating with a first neighbor device discovered at a first location, and the second set of distributed antenna elements generally aligned in a second linear direction are associated with second data for communicating with a second neighbor device discovered at a second location different from the first location, the method further comprising:

sending the first data to the second device; and

sending the second data to the first device.

18. The method of claim 17, further comprising:

receiving, from one of the first and the second device, third data for communicating with a third neighbor device at a third location; and

storing the third data in a memory device.

19. The method of claim 14, wherein selecting the first and second combinations of the distributed antenna elements includes selecting additional parameters for forming the radiation pattern including resonant frequency band parameters.