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Method and apparatus for selectively activating radio frequency identification tags that are in close proximity
| Details |
Inventors: Collins, Timothy James; Rakers, Patrick L.; Rachwalski, Richard Stanley; Quaderer, James G.;
Assignee: Motorola, Inc. (Schaumberg, IL)
Primary Examiner: Wu; Daniel J.
Assistant Examiner: Nguyen; Tai T.
Attorney, Agent or Firm: Hughes; Terri S.
A radio frequency identification exciter (200) includes a plurality of antenna elements (122a-i) that are spaced to define active areas (130a-e). A matrix switch (202) flexibly connects the plurality of antenna elements to an exciter circuit (203). Independent switches (204a-i) are selectively switched such that an electric field is generated between at least two antenna elements whereby radio frequency identification tags (132) in the vicinity of the two antenna elements are capacitively powered to exchange data with the exciter. Antenna elements other than the at least two antenna elements may be selectively coupled to a signal from the exciter circuit that inhibits activation of radio frequency identification tags in the vicinity of those antenna elements. The matrix switch preferably comprises polymer-based circuits. |
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DETAILED DESCRIPTION We claim: 1.
An apparatus for capacitively powering radio frequency identification devices, the apparatus comprising: a plurality of antenna elements; an exciter, coupled to at least a first portion of the plurality of antenna elements, to provide an excitation signal used to selectively energize the first portion of the plurality of antenna elements; and a switch selectively coupled to at least one of the plurality of antenna elements and the exciter, wherein the exciter has a first potential terminal and a second potential terminal, and wherein at least one of the first potential terminal and the second potential terminal emits a radio frequency signal, and wherein a first antenna element of the plurality of antenna elements is coupled to the first potential terminal by the switch and a second antenna element is coupled to the second potential terminal by the switch such that a radio frequency identification tag between the first and second antenna elements is energized.
2.
The apparatus of claim 1 further comprising a receiver coupled to at least a second portion of the plurality of antenna elements, and wherein the switch is selectively coupled to the receiver.
3.
The apparatus of claim 1 wherein the apparatus is coupled to ground.
4.
The apparatus of claim 1 wherein the plurality of antenna elements are electrostatic antenna elements.
5.
The apparatus of claim 1 wherein at least one of the following elements is disposed on a substrate: the plurality of antenna elements, and the switch.
6.
The apparatus of claim 5 wherein the substrate is selected from a group consisting of: contact paper, shelf lining, paper, plastic, rubber, and wood.
7.
The apparatus of claim 1 wherein the switch comprises a plurality of independent switches, and wherein one independent switch of the plurality of independent switches controls at least one antenna element of the plurality of antenna elements, and wherein each of the plurality of independent switches is controllable separately by a switch control circuit
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Telecommunications 
