Passive SAW-ID tags using a chirp transducer
First Claim
1. An SAW-ID tag device, comprising:
- a piezoelectric substrate with temperature-stable characteristics, having a top surface and a bottom surface;
an upper bus bar, a lower bus bar, a plurality of electrode taps and an input chirped SAW transducer disposed on said top surface of the piezoelectric substrate;
said input chirped SAW transducer being capable of providing a dispersive, complementary matched filter response to a chirp waveform input signal and being connected to said upper bus bar and said lower bus bar;
a built-in antenna being connected to said upper bus bar and said lower bus bar;
said plurality of electrode taps being disposed between said upper bus bar and said lower bus bar and being connected to said upper bus bar and said lower bus bar;
a transmitter generating an expanded FM chirp waveform;
said plurality of electrode taps being spaced at predetermined distances from each other establishing a time-ordered code;
said input chirped SAW transducer, receiving said expanded FM chirp waveform as an expanded input chirp signal through said antenna and compressing said input expanded chirp signal into a narrow, compressed pulse signal propagating toward said plurality of electrode taps;
said plurality of electrode taps producing a plurality of narrow, compressed pulse samples propagating a time-ordered pulse train output to said antenna; and
said antenna transmitting a time-ordered pulse train output signal back to a means for interrogation identifying said SAW-ID tag device.
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Accused Products
Abstract
A Passive Surface Acoustic Wave Identification Tag ("SAW-ID tag") device utilizes pulse compression techniques and a large number of coding possibilities for identifying articles at enhanced ranges. The SAW-ID tag device provides a piezoelectric substrate having bus bars, spaced electrode taps between the bus bars and a built-in antenna, with an input chirped SAW transducer having a dispersive, complementary matched filter response to an input expanded chirp signal from an expanded linear FM chirp waveform actively generated by a nearby chirp transmitter. The input expanded chirp signal is fed into the input chirped SAW transducer through the built-in antenna, to compresses the input expanded chirp signal into a narrow, compressed pulse signal propagating toward the electrodes taps. The spacing of the electrode taps establishes the desired unique time-ordered coding. The electrode taps sample the narrow, compressed pulse signal and provide narrow, compressed pulse samples propagating a coded, pulse train output transmitted via the antenna to a nearby interrogation means to identify the tagged article. The preferred embodiment is an SAW-ID tag device with a piezoelectric quartz substrate about 1 inch long, a built-in dipole antenna and five (5) spaced electrode taps, establishing several million coding possibilities. Also disclosed are methods of identifying articles using an SAW-ID tag device, and methods of selectively disconnecting and connecting electrodes to facilitate mass production.
55 Citations
48 Claims
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1. An SAW-ID tag device, comprising:
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a piezoelectric substrate with temperature-stable characteristics, having a top surface and a bottom surface; an upper bus bar, a lower bus bar, a plurality of electrode taps and an input chirped SAW transducer disposed on said top surface of the piezoelectric substrate; said input chirped SAW transducer being capable of providing a dispersive, complementary matched filter response to a chirp waveform input signal and being connected to said upper bus bar and said lower bus bar; a built-in antenna being connected to said upper bus bar and said lower bus bar; said plurality of electrode taps being disposed between said upper bus bar and said lower bus bar and being connected to said upper bus bar and said lower bus bar; a transmitter generating an expanded FM chirp waveform; said plurality of electrode taps being spaced at predetermined distances from each other establishing a time-ordered code; said input chirped SAW transducer, receiving said expanded FM chirp waveform as an expanded input chirp signal through said antenna and compressing said input expanded chirp signal into a narrow, compressed pulse signal propagating toward said plurality of electrode taps; said plurality of electrode taps producing a plurality of narrow, compressed pulse samples propagating a time-ordered pulse train output to said antenna; and said antenna transmitting a time-ordered pulse train output signal back to a means for interrogation identifying said SAW-ID tag device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An SAW-ID tag device, comprising:
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a piezoelectric quartz substrate having a top surface and a bottom surface; an upper bus bar, a lower bus bar, five electrode taps, a built-in antenna and an input chirped SAW transducer disposed on said top surface of the piezoelectric quartz substrate; said input chirped SAW transducer being capable of providing a dispersive, complementary matched filter response to a chirp waveform input signal and being connected to said upper bus bar and said lower bus bar; said upper bus bar and said lower bus bar extending in a generally linear fashion and running substantially parallel to each other; said five electrode taps being connected to said upper bus bar and said lower bus bar; said five electrode taps being orthogonally disposed between said upper bus bar and said lower bus bar and being spaced at a plurality of predetermined distances from each other establishing a time-ordered code; a transmitter placed in proximity to said piezoelectric quartz substrate generating an expanded FM chirp waveform; said input chirped SAW transducer receiving said expanded FM chirp waveform as an expanded input chirp signal through said antenna and compressing said expanded input chirp signal into a narrow, compressed pulse signal which propagates toward said five electrode taps; said five electrode taps producing five narrow, compressed pulse samples propagating a time-ordered pulse train output to said antenna; and said antenna transmitting a time-ordered pulse train output signal back to a means for interrogation identifying said SAW-ID tag device. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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18. A method of identifying articles using an SAW-ID tag device, comprising the steps of:
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selecting a piezoelectric substrate having a polished top surface, a bottom surface and temperature-stable characteristics; forming an input chirped SAW transducer being capable of providing a dispersive, complementary matched filter response to a chirp waveform input signal on said top surface of the piezoelectric substrate; connecting an upper bus bar and a lower bus bar to said input chirped SAW transducer on said top surface of the piezoelectric substrate and connecting a built-in antenna to said upper bus bar and said lower bus bar; disposing a plurality of electrode taps between said upper bus bar and said lower bus bar; spacing said electrode taps at selected distances from each other between said upper bus bar and lower bus bar, thereby determining a sequence of time-ordered signals forming a time-ordered code; generating an expanded FM chirp waveform from a chirp transmitter as an expanded input chirp signal; feeding said expanded input chirp signal through said antenna to said input chirped SAW transducer, said input chirped SAW transducer having a dispersive, complementary matched filter response to said expanded input chirp signal; compressing said input expanded chirp signal into a narrow, compressed pulse signal; propagating said narrow, compressed pulse signal toward said plurality of electrode taps forming said time-ordered code; allowing said plurality of electrode taps to sample said narrow, compressed pulse signal in order to produce a plurality of narrow, compressed pulse samples; and propagating a uniquely coded time-ordered pulse train output through said antenna back to a means for interrogation identifying the SAW-ID tagged article. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25)
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26. A method of identifying articles using an SAW-ID tag device comprising the steps of:
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selecting a piezoelectric substrate having a polished top surface, a bottom surface and temperature-stable characteristics; forming an input chirped SAW transducer being capable of providing a dispersive, complementary matched filter response to a chirp waveform input signal on said top surface of the piezoelectric substrate; connecting an upper bus bar and a lower bus bar to said input chirped SAW transducer on said top surface of the piezoelectric substrate and connecting a built-in antenna to said upper bus bar and said lower bus bar; disposing a plurality of electrode taps between said upper bus bar and said lower bus bar; forming a plurality of connected electrode taps from said plurality of electrode taps with a plurality of upper connective portions connecting each of said plurality of connected electrode taps to said upper bus bar and a plurality of lower connective portions connecting each of said plurality of connected electrode taps to said lower bus bar; selectively disconnecting a predetermined number of said plurality of connected electrode taps from said upper bus bar and said lower bus bar with a cutting means forming a set of operational electrode taps; said set of operational electrode taps determining said sequence of time-ordered signals forming said time-ordered code; generating an expanded FM chirp waveform from a chirp transmitter as an expanded input chirp signal; feeding said input expanded chirp signal through said antenna to said input chirped SAW transducer; compressing said input expanded chirp signal into a narrow, compressed pulse signal; propagating said narrow, compressed pulse signal toward said set of operational electrode taps forming said time-ordered code; allowing said set of operational electrode taps to sample said narrow, compressed pulse signal in order to produce a plurality of narrow, compressed pulse samples; and propagating a uniquely coded time-ordered pulse train output through said antenna back to a means for interrogation identifying the SAW-ID tagged article. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
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38. A method of identifying articles using an SAW-ID tag device, comprising the steps of:
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selecting a piezoelectric substrate having a polished top surface, a bottom surface and temperature-stable characteristics; forming an input chirped SAW transducer being capable of providing a dispersive, complementary matched filter response to a chirp waveform input signal on said top surface of the piezoelectric substrate; connecting an upper bus bar and a lower bus bar to said input chirped SAW transducer on said top surface of the piezoelectric substrate and connecting a built-in antenna to said upper bus bar and said lower bus bar; forming a plurality of electrode taps having a plurality of top conductive wire bonds and a plurality of bottom conductive wire bonds; forming said upper bus bar and said lower bus bar in a generally linear fashion running substantially parallel to each other, having a plurality of opposing slots dimensioned to accept said plurality of top conductive wire bonds bridging said opposing slots of the upper bus bar and to accept said plurality of bottom conductive wire bonds bridging said opposing slots of the lower bus bar; disposing said plurality of electrode taps between said upper bus bar and said lower bus bar; forming a plurality of connected electrode taps by selectively connecting said plurality of top conductive wire bonds to said upper bus bar and said plurality of bottom conductive wire bonds to said lower bus bar; spacing said plurality of connected electrode taps at selected distances from each other between said upper bus bar and lower bus bar, thereby determining a sequence of time-ordered signals forming a time-ordered code; generating an expanded FM chirp waveform from a chirp transmitter as an expanded input chirp signal; feeding said expanded input chirp signal through said antenna to said input chirped SAW transducer; compressing said expanded input chirp signal into a narrow, compressed pulse signal; propagating said narrow, compressed pulse signal toward said plurality of connected electrode taps forming said time-ordered code; allowing said plurality of connected electrode taps to sample said narrow, compressed pulse signal in order to produce a plurality of narrow, compressed pulse samples; and propagating a uniquely coded time-ordered pulse train output through said antenna back to a means for interrogation identifying the SAW-ID tagged article. - View Dependent Claims (39, 40, 41, 42, 43, 44, 45, 46, 47, 48)
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Specification