Radio frequency detection and identification system
First Claim
1. A system for detecting the presence of an article comprising:
- a transmitter for radiating a first electromagnetic signal at a predetermined primary frequency;
a tag comprising at least one generally planar conductive pattern, said tag being arranged to be secured to the article for generating a second electromagnetic signal in response to receiving the first electromagnetic signal, the second electromagnetic signal being at the primary frequency and at a predetermined secondary frequency, different from the primary frequency;
a receiver for receiving the second electromagnetic signal; and
a computer connected to an output of the receiver, said computer processing the received second electromagnetic signal and generating an output signal when the secondary frequency is detected in the second electromagnetic signal.
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Accused Products
Abstract
A system is disclosed for detecting the presence of an article. The system includes a transmitter for radiating a first electromagnetic signal at a predetermined primary frequency and a resonant tag secured to the article. The resonant tag generates a second electromagnetic signal in response to receiving the first electromagnetic signal. The second electromagnetic signal has components at the primary frequency and at a predetermined secondary frequency different from the primary frequency. The system also includes a receiver for receiving the second electromagnetic signal and a computer connected to an output of the receiver. The computer processes the received second electromagnetic signal and generates an output signal when the secondary frequency is detected in the second electromagnetic signal.
33 Citations
25 Claims
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1. A system for detecting the presence of an article comprising:
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a transmitter for radiating a first electromagnetic signal at a predetermined primary frequency;
a tag comprising at least one generally planar conductive pattern, said tag being arranged to be secured to the article for generating a second electromagnetic signal in response to receiving the first electromagnetic signal, the second electromagnetic signal being at the primary frequency and at a predetermined secondary frequency, different from the primary frequency;
a receiver for receiving the second electromagnetic signal; and
a computer connected to an output of the receiver, said computer processing the received second electromagnetic signal and generating an output signal when the secondary frequency is detected in the second electromagnetic signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 18, 21, 22, 23, 24, 25)
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8. A system for determining the presence of information stored in a plurality of resonant frequency circuits having different resonant frequencies, the system comprising:
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a transmitter for radiating a first electromagnetic signal at a predetermined primary frequency;
a tag including the plurality of resonant circuits, each of which comprises a generally planar conductive pattern on the tag and each of the resonant circuits resonating at one of the different resonant frequencies, said tag receiving the first electromagnetic signal and generating a second electromagnetic signal in response to receiving the first electromagnetic signal, the second electromagnetic signal comprising a plurality of secondary frequencies, each of the secondary frequencies corresponding to one of the resonant frequencies of the plurality of resonant circuits;
a receiver for receiving the second electromagnetic signal; and
a computer connected to the output of the receiver, said computer processing the received second electromagnetic signal to detect the presence of the plurality of secondary frequencies and generating an output signal corresponding to the information. - View Dependent Claims (9, 10, 11)
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12. A method for detecting the presence of an article comprising the steps of:
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securing a tag, having a plurality of resonant circuits each of which comprises a generally planar conductive pattern on the tag, to the article;
transmitting a first electromagnetic signal at a predetermined primary frequency;
generating a second electromagnetic signal in response to the resonant tag receiving the first electromagnetic signal, the second electromagnetic signal being at the primary frequency and at a predetermined second frequency different from the primary frequency;
receiving the second electromagnetic signal; and
processing the received second electromagnetic signal and generating an output signal when the secondary frequency is detected in the second electromagnetic signal. - View Dependent Claims (13, 14, 15)
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16. A method for determining the presence of information stored in a plurality of resonant circuits having different resonant frequencies, comprising the steps of:
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providing a tag including the plurality of resonant circuits each of which comprises a generally planar conductive pattern;
radiating a first electromagnetic signal at a predetermined primary frequency;
receiving the first electromagnetic signal by the resonant tag and generating a second electromagnetic signal in response to receiving the first electromagnetic signal, the second electromagnetic signal comprising a plurality of secondary frequencies, each of the secondary frequencies corresponding to one of the resonant frequencies of the plurality of resonant circuits;
receiving the second electromagnetic signal; and
processing the received second electromagnetic signal to detect the presence of the plurality of secondary frequencies and generating an output signal corresponding to the information. - View Dependent Claims (17)
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19. A system for detecting the presence of an article comprising:
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a transmitter for radiating a first electromagnetic signal at only a predetermined primary frequency;
a tag, having a plurality of resonant circuits each of which comprises a generally planar conductive pattern on the tag, and being arranged to be secured to the article for generating a second electromagnetic signal in response to receiving said first electromagnetic signal, said second electromagnetic signal being at said primary frequency and at a predetermined secondary frequency, different from said primary frequency;
a receiver for receiving said second electromagnetic signal; and
a computer connected to an output of the receiver, said computer processing the received second electromagnetic signal and generating an output signal when said secondary frequency is detected in said second electromagnetic signal. - View Dependent Claims (20)
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Specification