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US 2010/0060429 A1Published application
Saw Sensor Tags with Enhanced Performance
AssigneeApplied Sensor Research & Development Corporation
InventorsJacqueline H. Hines, Leland P. Solie
Life of this patent
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Abstract
The subject of the present invention is a set of SAW (surface acoustic wave) based sensor tag device embodiments system for remotely sensing and/or providing identification information. These sensor/tag devices would operate in a system which consists of one or more uniquely identifiable sensor/tag devices and a wireless interrogator. The sensor device incorporates an antenna for receiving incident RF energy and re-radiating the tag identification number and the sensor measured parameter(s). Since there is no power source in or connected to the sensor, it is a passive sensor. As such the device is elegantly simple, low-cost, and rugged. The device is wirelessly interrogated by the interrogator which is described elsewhere.
Claims11
A coded surface acoustic wave device, comprising
- (a) a piezoelectric substrate;
- (b) at least one first transducer arranged on at least a portion of said piezoelectric substrate wherein said first transducer has electrode structures that vary in width and separation so as to be capable of generating and receiving acoustic waves at frequencies that vary along the transducer in the direction of acoustic wave propagation;
- (c) at least one second surface acoustic wave element formed on said piezoelectric substrate and spaced from said first transducer along the direction of acoustic wave propagation, said at least one second surface acoustic wave element comprising sub elements, each of which comprises electrode structures capable of interacting with acoustic waves at frequencies that correspond to a subset of the frequencies generated by said first transducer;
- (d) wherein said sub-elements of said at least one second surface acoustic wave element are spatially distributed along said piezoelectric substrate in the direction of acoustic wave propagation;
- and wherein said at least one second surface acoustic wave element is structured such that said sub-elements of said second surface acoustic wave element are spaced at different positions in the direction of acoustic wave propagation relative to the corresponding portion of said first transducer, so as to effect different delays to each of said sub-elements, thereby effecting a code.
2 more elements
A coded surface acoustic wave device, comprising
- (e) a piezoelectric substrate;
- (a) at least one first transducer arranged on at least a portion of said piezoelectric substrate wherein said first transducer has electrode structures that vary in width and separation so as to be capable of generating and receiving acoustic waves at frequencies that vary along the transducer in the direction of acoustic wave propagation;
- (b) at least one second surface acoustic wave element formed on said piezoelectric substrate and spaced from said first transducer along the direction of acoustic wave propagation, said at least one second surface acoustic wave element comprising sub elements, each of which comprises electrode structures capable of interacting with acoustic waves at frequencies that correspond to a subset of the frequencies generated by said first transducer;
- (c) wherein said sub-elements of said at least one second surface acoustic wave element are spatially distributed along said piezoelectric substrate in the direction of acoustic wave propagation;
- and wherein said at least one second surface acoustic wave element is structured such that said sub-elements of said second surface acoustic wave element are spaced at different positions in the direction of acoustic wave propagation relative to the corresponding portion of said first transducer, so as to effect different delays to each of said sub-elements, thereby effecting a code;
- and
- (d) wherein said second surface acoustic wave element is connected to a non-linear device operable to generate a harmonic response.
4 more elements
A coded surface acoustic wave device, comprising
- (a) a piezoelectric substrate;
- (b) at least one first transducer arranged on at least a portion of said piezoelectric substrate wherein said first transducer has electrode structures that vary in width and separation so as to be capable of generating and receiving acoustic waves at frequencies that vary along the transducer in the direction of acoustic wave propagation;
- (c) at least one second surface acoustic wave element formed on said piezoelectric substrate and spaced from said first transducer along the direction of acoustic wave propagation, said at least one second surface acoustic wave element comprising sub elements, each of which comprises electrode structures capable of interacting with acoustic waves at frequencies that correspond to a subset of the frequencies generated by said first transducer;
- (d) wherein said sub-elements of said at least one second surface acoustic wave element are spatially distributed along said piezoelectric substrate in the direction of acoustic wave propagation;
- and wherein said at least one second surface acoustic wave element is structured such that said sub-elements of said second surface acoustic wave element are spaced at different positions in the direction of acoustic wave propagation relative to the corresponding portion of said first transducer, so as to effect different delays to each of said sub-elements, thereby effecting a code;
- and
- (e) wherein said first transducer is connected to a non-linear device operable to generate a harmonic response.
4 more elements
A wireless interface device for one or more external sensors that respond to changes in environmental parameters with a change in voltage, comprising:
- (a) a piezoelectric substrate;
- (b) at least one first transducer arranged on at least a portion of said piezoelectric substrate wherein said first transducer has electrode structures that vary in width and separation so as to be capable of generating and receiving acoustic waves in spatially adjacent acoustic tracks at frequencies that vary laterally across the transducer acoustic aperture in the direction perpendicular to the direction of acoustic wave propagation;
- (c) at least one second surface acoustic wave element formed on said piezoelectric substrate and spaced from said first transducer along the direction of acoustic wave propagation, said at least one second surface acoustic wave element comprising sub elements, each of which comprises electrode structures capable of interacting with acoustic waves at frequencies that correspond to a subset of the frequencies generated by said first transducer;
- (d) wherein said sub-elements of said at least one second surface acoustic wave element are spatially distributed laterally across the acoustic aperture to match the lateral spatial distribution of frequencies in said first transducer;
- and wherein said at least one second surface acoustic wave element is structured such that said sub-elements of said second surface acoustic wave element are spaced at different positions in the direction of acoustic wave propagation relative to the corresponding portion of said first transducer, so as to effect different delays within each of said acoustic tracks, thereby effecting a code;
- (e) wherein at least one of said sub-elements of said second surface acoustic wave element comprise a transducer that is electrically connected to one of said at least one external sensors;
- and
- (f) wherein changes in properties of the external sensor result in a change in properties of the surface acoustic wave reflected by said sub-element connected to said external sensor.
5 more elements
Dependencies are inferred from the claim text.