System and method of detecting items identified by radio frequency identification (rfid) tags in a smart shopping cart

Patent metadata

Field	Value
Publication number	US-2016180670-A1
Application number	US-201414574991-A
Country	US
Kind code	A1
Filing date	Dec 18, 2014
Priority date	Dec 18, 2014
Publication date	Jun 23, 2016
Grant date	—

Abstract

A smart shopping cart includes a basket having an open top, a plurality of electrically conductive side walls, and an electrically conductive bottom wall. Unidirectional, near-field, side antenna elements are mounted on, and electrically grounded to, the side walls. Each side antenna element radiates an electromagnetic field in an inward direction toward an interior of the basket. A near-field, bottom antenna element is mounted on, and electrically grounded to, the bottom wall, and radiates an electromagnetic field in an upward direction toward the interior of the basket. A cart controller excites all the antenna elements to create a composite, resonant electromagnetic field substantially within the basket with substantially no electromagnetic field leakage exteriorly past the side walls, and detects entry and exit of RFID-tagged items through the open top of the basket into and out of the resonant electromagnetic field.

First claim

1 . A system for detecting items identified by radio frequency identification (RFID) tags, comprising:
a shopping cart including a basket having an open top, the basket having a plurality of electrically conductive side walls and an electrically conductive bottom wall; a plurality of unidirectional, near-field, side antenna elements mounted on, and electrically grounded to, the side walls, each side antenna element being operative for radiating an electromagnetic field in an inward direction toward an interior of the basket; a near-field, bottom antenna element mounted on, and electrically grounded to, the bottom wall, and operative for radiating an electromagnetic field in an upward direction toward the interior of the basket; and a cart controller supported by the cart, for exciting all the antenna elements to create a composite, resonant electromagnetic field substantially within the basket with substantially no electromagnetic field leakage exteriorly past the side walls, and for detecting entry and exit of each RFID-tagged item through the open top of the basket into and out of the resonant electromagnetic field.

2 . The system of claim 1 , wherein the cart includes a mobile chassis for supporting the basket above a lower shelf; and wherein the bottom antenna element is bidirectional, and also radiates an electromagnetic field in a downward direction toward the lower shelf; and wherein the cart controller is also operative for detecting placement and removal of each RFID-tagged item on and from the lower shelf.

3 . The system of claim 1 , wherein each side wall and the bottom wall are comprised of a grid of electrically conductive, spaced-apart rods that cross each other.

4 . The system of claim 1 , wherein each side antenna element has a ground plane that is electrically grounded to a respective side wall to contain the resonant electromagnetic field substantially within the basket.

5 . The system of claim 1 , wherein the side walls include a right side wall, a left side wall opposite to the right side wall, a front side wall extending between the right and left side walls at a front of the cart, and a back side wall extending between the right and left side walls at a back of the cart; and wherein the side antenna elements are mounted on at least two of the right, left, front, and back, side walls.

6 . The system of claim 1 , and a cart processing subsystem mounted on the cart and supporting the cart controller, and wherein the cart processing subsystem includes a transmit/receive processor for exciting the antenna elements.

7 . The system of claim 6 , and a host processing subsystem mounted remotely from the cart processing subsystem, and being in wireless communication with the cart processing subsystem.

8 . The system of claim 6 , wherein the cart processing subsystem includes an indicator for indicating the entry and exit of each RFID-tagged item through the open top of the basket.

9 . The system of claim 6 , wherein the resonant electromagnetic field is tuned to an RFID frequency on the order of 900 MHz.

10 . The system of claim 1 , wherein the antenna elements are excited simultaneously.

11 . A method of detecting items identified by radio frequency identification (RFID) tags, comprising:
configuring a shopping cart with a basket having an open top, and with a plurality of electrically conductive side walls and an electrically conductive bottom wall; mounting a plurality of unidirectional, near-field, side antenna elements on, and electrically grounding the side antenna elements to, the side walls; mounting a near-field, bottom antenna element on, and electrically grounding the bottom antenna element to, the bottom wall; exciting each side antenna element to radiate an electromagnetic field in an inward direction toward an interior of the basket; exciting the bottom antenna element to radiate an electromagnetic field in an upward direction toward the interior of the basket; the exciting of all the antenna elements creating a composite, resonant electromagnetic field substantially within the basket with substantially no electromagnetic field leakage exteriorly past the side walls; and detecting entry and exit of each RFID-tagged item through the open top of the basket into and out of the resonant electromagnetic field.

12 . The method of claim 11 , and supporting the basket above a lower shelf; and configuring the bottom antenna element to be bidirectional such that the bottom antenna element also radiates an electromagnetic field in a downward direction toward the lower shelf; and detecting placement and removal of each RFID-tagged item on and from the lower shelf

13 . The method of claim 11 , and configuring each side wall and the bottom wall to be comprised of a grid of electrically conductive, spaced-apart rods that cross each other.

14 . The method of claim 11 , and configuring each side antenna element with a ground plane that is electrically grounded to a respective side wall to contain the resonant electromagnetic field substantially within the basket.

15 . The method of claim 11 , and configuring the side walls to include a right side wall, a left side wall opposite to the right side wall, a front side wall extending between the right and left side walls at a front of the cart, and a back side wall extending between the right and left side walls at a back of the cart; and mounting the side antenna elements on at least two of the right, left, front, and back, side walls.

16 . The method of claim 11 , and supporting a cart controller on the cart, and wherein the exciting of the antenna elements is performed with a transmit/receive processor.

17 . The method of claim 16 , and mounting a host processing subsystem remotely from the cart controller.

18 . The method of claim 16 , and indicating the entry and exit of each RFID-tagged item through the open top of the basket.

19 . The method of claim 16 , and tuning the resonant electromagnetic field to an RFID frequency on the order of 900 MHz.

20 . The method of claim 11 , wherein the exciting of the antenna elements is performed simultaneously.

Assignees

• Symbol Technologies Inc

Inventors

• Swope Charles B

Classifications

• G08B13/246 Primary

  Check out systems combined with EAS, e.g. price information stored on EAS tag (anti-theft systems in point of sale systems G07G3/003) · CPC title

• G08B13/2417

  having a radio frequency identification chip · CPC title

• G08B13/2485

  Simultaneous detection of multiple EAS tags · CPC title

• G08B13/2474

  Antenna or antenna activator geometry, arrangement or layout (loop antennae H01Q1/22) · CPC title