Extended range passive wireless tag system and method
First Claim
1. A passive wireless tag assembly responsive to a wireless interrogator signal from an interrogator by reflecting a return signal derived from the wireless interrogator signal, the return signal containing information added by said passive wireless tag assembly, said passive wireless tag assembly comprising:
- at least one SAW circuit operable for receiving the wireless interrogator signal as an incoming electromagnetic wave, transforming the electromagnetic wave into a surface acoustic wave, and then transforming the surface acoustic wave back into a subsequent outgoing electromagnetic wave serving as the return signal;
an information circuit constructed and arranged to add information to at least one of the surface acoustic wave, the incoming electromagnetic wave, and the subsequent outgoing electromagnetic wave;
at least one pair of antennas, each pair connected in a Van Atta array by transmission lines with one another and with said at least one SAW circuit and said information circuit and being constructed and arranged to receive the wireless interrogator signal and transmit the return signal in a direction from whence the wireless interrogator signal came;
a first conductive surface and a second conductive surface connected at a right angle to one another to form a corner reflector for providing vertical and horizontal steering of the interrogator signal, said at least one pair of antennas being positioned on said first conductive surface; and
at least one passive modulation circuit positioned on said first conductive surface and operatively connected to the SAW circuit to provide vertical steering of the interrogator signal, the passive wireless tag assembly further comprising at least one antenna positioned on said second conductive surface to provide horizontal steering of the interrogator signal and to form, in conjunction with said first conductive surface, a dihedral corner reflector.
1 Assignment
0 Petitions
Accused Products
Abstract
A passive wireless tag assembly comprises a plurality of antennas and transmission lines interconnected with circuitry and constructed and arranged in a Van Atta array or configuration to reflect an interrogator signal in the direction from where it came. The circuitry may comprise at least one surface acoustic wave (SAW)-based circuit that functions as a signal reflector and is operatively connected with an information circuit. In another embodiment, at least one delay circuit and/or at least one passive modulation circuit(s) are utilized. In yet another embodiment, antennas connected to SAW-based devices are mounted to at least one of the orthogonal surfaces of a corner reflector.
49 Citations
16 Claims
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1. A passive wireless tag assembly responsive to a wireless interrogator signal from an interrogator by reflecting a return signal derived from the wireless interrogator signal, the return signal containing information added by said passive wireless tag assembly, said passive wireless tag assembly comprising:
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at least one SAW circuit operable for receiving the wireless interrogator signal as an incoming electromagnetic wave, transforming the electromagnetic wave into a surface acoustic wave, and then transforming the surface acoustic wave back into a subsequent outgoing electromagnetic wave serving as the return signal; an information circuit constructed and arranged to add information to at least one of the surface acoustic wave, the incoming electromagnetic wave, and the subsequent outgoing electromagnetic wave; at least one pair of antennas, each pair connected in a Van Atta array by transmission lines with one another and with said at least one SAW circuit and said information circuit and being constructed and arranged to receive the wireless interrogator signal and transmit the return signal in a direction from whence the wireless interrogator signal came; a first conductive surface and a second conductive surface connected at a right angle to one another to form a corner reflector for providing vertical and horizontal steering of the interrogator signal, said at least one pair of antennas being positioned on said first conductive surface; and at least one passive modulation circuit positioned on said first conductive surface and operatively connected to the SAW circuit to provide vertical steering of the interrogator signal, the passive wireless tag assembly further comprising at least one antenna positioned on said second conductive surface to provide horizontal steering of the interrogator signal and to form, in conjunction with said first conductive surface, a dihedral corner reflector. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A passive wireless radio frequency identification tag system comprising:
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an interrogator operable to produce a wireless interrogator signal; and a passive wireless tag assembly comprising, at least one delay circuit operable for delaying an electromagnetic wave entering said at least one delay circuit by a predetermined time delay τ
;at least one frequency responsive circuit comprising a transfer function that is a function of frequency, and wherein said circuit is operable for adding information to said wireless interrogator signal, said information being derived from said transfer function; and at least one pair of antennas, each pair of antennas being operatively connected with a corresponding one of said at least one delay circuit and one of said at least one frequency responsive circuit, and each antenna being configured to receive the wireless interrogator signal, for creating a time reversal of the incoming electromagnetic wave such that the subsequent outgoing return signal transmits predominantly in a direction from whence said interrogator signal came, wherein for each combination of said at least one pair of antennas operatively connected with a corresponding one of said at least one delay circuit and of said at least one frequency responsive circuit, such combination is configured to produce at least three signals in response to said wireless interrogator signal, wherein only the return signal is steerable in the direction from whence the interrogator signal came, wherein the return signal is received at said interrogator at a time t≈
τ
+t0, t0 being a variable known as two-way propagation delay corresponding to a two way travel time of a distance between said interrogator and said passive wireless tag assembly, and wherein a first additional non-steered signal is produced from said passive wireless tag assembly and received by said interrogator at a time t≈
t0, and a second additional non-steered signal is produced from said passive wireless tag assembly and received by said interrogator at a time t≈
2τ
+t0. - View Dependent Claims (14, 15)
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16. A passive wireless radio frequency identification tag system comprising:
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an interrogator operable to produce a wireless interrogator signal; and a passive wireless tag assembly comprising, at least one delay circuit operable for delaying an electromagnetic wave entering said at least one delay circuit by a predetermined time delay τ
;at least two frequency responsive circuits for each at least one delay circuit, each responsive circuit comprising a transfer function that is a function of frequency, and wherein said circuit is operable for adding information to said wireless interrogator signal, said information being derived from said transfer function; and at least one pair of antennas, and each antenna being configured to receive the wireless interrogator signal, for creating a time reversal of the incoming electromagnetic wave such that the subsequent outgoing return signal transmits predominantly in a direction from whence said interrogator signal came, wherein each antenna of said at least one pair of antennas is operatively connected to one of said two frequency responsive circuits at a first port of each, wherein each corresponding delay circuit is operatively connected to a second port of each of the two frequency responsive circuits so as to be positioned therebetween in order to produce at least three signals in response to said wireless interrogator signal, wherein only the return signal is steerable in the direction from whence the interrogator signal came, wherein the return signal being transmitted is received at said interrogator at a time t≈
τ
+t0, t0 being a two-way propagation delay corresponding to a two way travel time of a distance between said interrogator and said passive wireless tag assembly, wherein a first additional non-steered signal, corresponding to out-of-band components of a first of the two frequency responsive circuits, is received from one antenna of said at least one pair of antennas, reflected by the first frequency responsive circuit, transmitted by the same one antenna of said at least one pair of antennas, and received by said interrogator at a time t≈
t0, and a second additional non-steered signal, corresponding to out-of-band components of the second of the two frequency responsive circuits, is received from the other antenna of said at least one pair of antennas, reflected by the second frequency responsive circuit, transmitted from the other antenna of said at least one pair of antennas, and received by said interrogator at a time t≈
t0.
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Specification