Security tag for use with article having inherent capacitance
First Claim
1. A security tag for use with an electronic security system for a surveilled area including transmitter means for transmitting into the surveilled area electromagnetic energy having a center frequency within a predetermined detection frequency range and receiver means for detecting within the surveilled area the presence of a security tag resonating at a frequency within the detection frequency range in response to said electromagnetic energy, the security tag for attachment to an article having an inherent capacitance, the security tag comprising:
- a dielectric substrate having a first side and a second side; and
circuitry means on the substrate for establishing a resonant circuit having a resonant frequency which is initially a predetermined frequency interval above the center frequency of the detection frequency range whereby upon attachment of the security tag to the article, the inherent capacitance of the article interacts with the resonant circuit to shift the resonant frequency of the resonant circuit downwardly, closer to the center frequency of the detection frequency range.
5 Assignments
0 Petitions
Accused Products
Abstract
A security tag for use with an electronic security system is used for attachment to an article having an inherent capacitance such as meat. The security system includes a transmitter for transmitting into a surveilled area electromagnetic energy having a center frequency within a predetermined detection frequency range and a receiver for detecting within the surveilled area the presence of a security tag resonating at a frequency within the detection frequency range in response to the electromagnetic energy. The tag includes a generally planar dielectric substrate having a first side and a second side. Circuitry on the substrate establishes a resonant circuit having a resonant frequency which is initially a predetermined frequency interval above the center frequency of the detection frequency range. Upon attachment of the security tag to the article, the inherent capacitance of the article interacts with the resonant circuit to shift the resonant frequency of the resonant circuit downwardly, closer to the center frequency of the detection frequency range.
196 Citations
5 Claims
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1. A security tag for use with an electronic security system for a surveilled area including transmitter means for transmitting into the surveilled area electromagnetic energy having a center frequency within a predetermined detection frequency range and receiver means for detecting within the surveilled area the presence of a security tag resonating at a frequency within the detection frequency range in response to said electromagnetic energy, the security tag for attachment to an article having an inherent capacitance, the security tag comprising:
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a dielectric substrate having a first side and a second side; and circuitry means on the substrate for establishing a resonant circuit having a resonant frequency which is initially a predetermined frequency interval above the center frequency of the detection frequency range whereby upon attachment of the security tag to the article, the inherent capacitance of the article interacts with the resonant circuit to shift the resonant frequency of the resonant circuit downwardly, closer to the center frequency of the detection frequency range. - View Dependent Claims (2, 3, 4, 5)
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Specification