Selectively responsive tag suitable for RFID systems and the like
First Claim
Patent Images
1. A tag responsive to a transmitted signal, comprising:
- a dielectric substrate;
an antenna supported on the substrate and defining an antenna pattern having a first electrical length selected to permit wireless interrogation by an external reader at one or more prescribed frequencies;
at least a first electrical contact at a first location along the antenna;
a conductive shunt conductively contacting the antenna at least at the first location and extending from the first location so as to define an antenna pattern having a second electrical length that is different than the first electrical length for so long as the conductive shunt remains in conductive contact with the antenna, the second electrical length precluding wireless interrogation by the external reader at the one or more prescribed frequencies; and
a carrier affixed to the shunt with a connection which is stronger than the conductive contact of the shunt to the antenna, the carrier being selectively movable away from the substrate to separate the conductive contact of the shunt to the antenna and restore the first electrical length of the antenna pattern.
1 Assignment
0 Petitions
Accused Products
Abstract
A tag for RFID applications and the like comprises an antenna supported on a dielectric substrate and having a first electrical length suitable for communication as a transponder. A selectively removable conductive shunt causes the antenna to assume a second electrical length which impedes transponder communication. Applications of the tag include tag-bearing products that are non-transmissive beneath surrounding packaging, and state machines that change between transmissive and non-transmissive states with selective shunting of the antenna. A method for enhancing an RFID tag for selective operation is also provided.
19 Citations
21 Claims
-
1. A tag responsive to a transmitted signal, comprising:
-
a dielectric substrate; an antenna supported on the substrate and defining an antenna pattern having a first electrical length selected to permit wireless interrogation by an external reader at one or more prescribed frequencies; at least a first electrical contact at a first location along the antenna; a conductive shunt conductively contacting the antenna at least at the first location and extending from the first location so as to define an antenna pattern having a second electrical length that is different than the first electrical length for so long as the conductive shunt remains in conductive contact with the antenna, the second electrical length precluding wireless interrogation by the external reader at the one or more prescribed frequencies; and a carrier affixed to the shunt with a connection which is stronger than the conductive contact of the shunt to the antenna, the carrier being selectively movable away from the substrate to separate the conductive contact of the shunt to the antenna and restore the first electrical length of the antenna pattern. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. A packaged tag-bearing product, comprising:
-
a tag including an antenna having an antenna pattern which is supported in fixed position relative to the product; a removable, conductive shunt positioned in conductive contact with at least one location on the antenna; and packaging disposed in surrounding relationship to the tag and the shunt, the packaging having a closed configuration in which the packaging precludes disruption of the contact between the at least one location and the shunt, wherein, in the presence of an electromagnetic signal of one or more prescribed frequencies, the tag responds with a signature signal only after the shunt has been removed. - View Dependent Claims (12, 13)
-
-
14. A method for enhancing an RFID tag for selective operation, the tag comprising an antenna having a first electrical length disposed on a dielectric substrate, the first electrical length being selected to permit wireless interrogation by an external reader at one or more prescribed frequencies, comprising the steps of:
-
providing at least a first electrical contact at a first location along the antenna; disposing a removable conductive shunt in conductive contact with the antenna at least at the first location and extending from the first location so as to define an antenna pattern having a second electrical length that is different than the first electrical length for so long as the conductive shunt remains in conductive contact with the antenna, the second electrical length precluding wireless interrogation by the external reader at the one or more prescribed frequencies; and affixing a carrier to the shunt with a connection which is stronger than the conductive contact of the shunt to the antenna, yet which is selectively separatable from the shunt, so as to permit selective restoration of the first electrical length of the antenna.
-
-
15. A tag constructed to have a non-transmissive state and a transmissive state, comprising:
-
a dielectric substrate; an antenna supported on the substrate and defining an antenna pattern having a first electrical length selected to permit wireless interrogation by an external reader at one or more prescribed frequencies; at least a first electrical contact at a first location along the antenna; a conductive shunt conductively contacting the antenna at least at the first location and extending from the first location so as to define an antenna pattern having a second electrical length that is different than the first electrical length and in which wireless interrogation at the one or more prescribed frequencies is precluded; and a disruptable mechanical connection made between the conductive shunt and at least the first location of the antenna, the connection establishing the non-transmissive state in which the antenna has the second electrical length and being disruptable to separate the conductive shunt from the antenna so as to thereafter establish the transmissive state in which the first electrical length of the antenna is restored. - View Dependent Claims (16, 17, 18, 19, 20, 21)
-
Specification