Multiple mode operated surface acoustic wave sensor for temperature compensation

Claim 2

A surface acoustic wave device sensor, comprising: a piezoelectric material, said piezoelectric material capable of propagating a surface acoustic wave in a first mode and a second mode; a selective coating having acoustic properties placed on said piezoelectric material, whereby an analyte exposed to said selective coating alters the acoustic properties of said selective coating; an input interdigital transducer and an output interdigital transducer are coupled to said piezoelectric material, whereby said input interdigital transducer generates a surface acoustic wave in the first and second mode on said selective coating of the piezoelectric material, said output interdigital transducer receiving said surface acoustic wave; a signal processor coupled to said transducer, said signal processor receiving signals representative of the surface acoustic wave propagated in the first and second mode and the acoustic properties of said selective coating, said signal processor separating a measurand effect from an environmental effect, whereby the analyte is detected due to a change in the acoustic properties of said selective coating; the first mode is a surface acoustic wave mode; and the second mode is a leaky surface acoustic wave mode.

Claim 3

A surface acoustic wave device sensor, as recited in claim 1 , further comprising said piezoelectric material is lithium tantalate.

Claim 4

A surface acoustic wave device sensor, as recited in claim 2 , wherein: said piezoelectric material is y-cut.

Claim 5

A surface acoustic wave device sensor, as recited in claim 2 , wherein: said piezoelectric material is rotated.

Claim 6

A surface acoustic wave device sensor, as recited in claim 4 , wherein: said piezoelectric material is 36° rotated y-cut.

Claim 7

A surface acoustic wave device sensor, as recited in claim 1 , further comprising said piezoelectric material is lithium niobate.

Claim 8

A surface acoustic wave device sensor, as recited in claim 6 , wherein: said piezoelectric material is y-cut.

Claim 9

A surface acoustic wave device sensor, as recited in claim 7 , wherein: said piezoelectric material is rotated.

Claim 10

A surface acoustic wave device sensor, as recited in claim 8 , wherein: said piezoelectric material is 128° rotated y-cut.

Claim 11

The surface acoustic wave device sensor, as recited in claim 1 , further comprising said output interdigital transducer placed on said piezoelectric material forms a delay line.

Claim 12

The surface acoustic wave device sensor, as recited in claim 1 , further comprising a first reflector placed on said piezoelectric material adjacent to said input interdigital transducer forms a resonator.

Claim 13

The surface acoustic wave device sensor, as recited in claim 11 , further comprising a second reflector is placed on said piezoelectric material between said first reflector and said second reflector.

Claim 14

A surface acoustic wave device sensor having a delay line configuration used to detect a substance, comprising: a piezoelectric material, said piezoelectric material propagating a surface acoustic wave in a first mode and a second mode; a selective coating having acoustic properties placed on said piezoelectric material, whereby a substance exposed to said selective coating alters the acoustic properties of said selective coating; an input signal transducer formed on said piezoelectric material causing said piezoelectric material to propagate the surface acoustic wave in the first and second modes; an output signal transducer formed on said piezoelectric material separated from said input signal transducer and having at least a portion of said selective coating between said input signal transducer and said output signal transducer, whereby the first and second modes are propagated through said selective coating; and a signal processor coupled to said input signal transducer and said output signal transducer calculates a delay time shift; said signal processor calculating a measurand effect based upon the first and second modes, whereby said measurand effect is separated from a temperature effect to provide temperature compensation and to permit detecting a plurality of changes in the acoustic properties of said selective coating of the substance despite environmental effects and independent of said temperature effect.

Claim 15

A surface acoustic wave device sensor having a delay line configuration used to detect a substance, comprising: a piezoelectric material, said piezoelectric material propagating a surface acoustic wave in a first mode and a second mode; a selective coating having acoustic properties placed on said piezoelectric material, whereby a substance exposed to said selective coating alters the acoustic properties of said selective coating; an input signal transducer formed on said piezoelectric material causing said piezoelectric material to propagate the surface acoustic wave in the first and second modes; an output signal transducer formed on said piezoelectric material separated from said input signal transducer and having at least a portion of said selective coating between said input signal transducer and said output signal transducer, whereby the first and second modes are propagated through said selective coating; and a signal processor coupled to said input signal transducer and said output signal transducer calculates a delay time shift; said signal processor calculating a measurand effect based upon the first and second modes, whereby said measurand effect is separated from a temperature effect to provide temperature compensation and to permit detecting a plurality of changes in the acoustic properties of said selective coating of the substance despite environmental effects and independent of said temperature effect.

Claim 16

A surface acoustic wave device sensor having a resonator configuration used to detect a substance, comprising: a piezoelectric material, said piezoelectric material capable of propagating a surface acoustic wave in a first mode and a second mode; a selective coating having acoustic properties placed on said piezoelectric material, whereby a substance exposed to said selective coating alters the acoustic properties of said selective coating; a signal transducer formed on said piezoelectric material causing said piezoelectric material to propagate the surface acoustic wave in the first and second modes; a first reflector formed on said piezoelectric material separated from said signal transducer and having at least a portion of said selective coating between said signal transducer and said first reflector, whereby the first and second modes are propagated through said selective coating; said signal transducer transmits the surface acoustic wave in the first and second modes to a signal processor; and said signal processor is coupled to said signal transducer, said signal transducer receives the surface acoustic wave in first and second modes, said signal processor calculating a measurand effect based upon the first and second modes, said measurand effect being separated from a temperature effect to provide temperature compensation, whereby changes in the acoustic properties of said selective coating caused by the substance are detected independent of said temperature effect.

Claim 17

A surface acoustic wave device sensor having a resonator configuration used to detect a substance, comprising: a piezoelectric material, said piezoelectric material capable of propagating a surface acoustic wave in a first mode and a second mode; a selective coating having acoustic properties placed on said piezoelectric material, whereby a substance exposed to said selective coating alters the acoustic properties of said selective coating; a signal transducer formed on said piezoelectric material causing said piezoelectric material to propagate the surface acoustic wave in the first and second modes; a first reflector formed on said piezoelectric material separated from said signal transducer and having at least a portion of said selective coating between said signal transducer and said first reflector, whereby the first and second modes are propagated through said selective coating; said signal transducer transmits the surface acoustic wave in the first and second modes to a signal processor; and said signal processor is coupled to said signal transducer, said signal transducer receives the surface acoustic wave in first and second modes, said signal processor calculating a measurand effect based upon the first and second modes, said measurand effect being separated from a temperature effect to provide temperature compensation, whereby changes in the acoustic properties of said selective coating caused by the substance are detected independent of said temperature effect.

Claim 18

A surface acoustic wave devise sensor having a resonator configuration, as recited in claim 14 , further comprising: a second reflector formed on said piezoelectric material so that said signal transducer is positioned between said first and second reflectors.

Claim 19

A surface acoustic wave device sensor, comprising: a piezoelectric material capable of simultaneously operating in at least two different modes, with each mode having a different response to an environmental effect; a selective coating placed on said piezoelectric material, whereby when a substance is placed in contact with said selective coating the acoustic properties of said selective coating are changed; means, coupled to said selective coating, for detecting the acoustic properties of the selective coating based upon a response of each of the two different modes; and means, coupled to said means for detecting, for identifying the substance placed in contact with said selective coating, whereby environmental effects, including a temperature effect are effectively removed due to the different responses of the at least two different modes and separating a measurand effect from said temperature effect provides temperature compensation to detect the changes in the acoustic properties caused by the substance independent of said temperature effect.

Claim 20

A surface acoustic wave device sensor, comprising: a piezoelectric material capable of simultaneously operating in at least two different modes, with each mode having a different response to an environmental effect; a selective coating placed on said piezoelectric material, whereby when a substance is placed in contact with said selective coating the acoustic properties of said selective coating are changed; means, coupled to said selective coating, for detecting the acoustic properties of the selective coating based upon a response of each of the two different modes; and means, coupled to said means for detecting, for identifying the substance placed in contact with said selective coating, whereby environmental effects, including a temperature effect are effectively removed due to the different responses of the at least two different modes and separating a measurand effect from said temperature effect provides temperature compensation to detect the changes in the acoustic properties caused by the substance independent of said temperature effect.

Claim 23

A method of detecting a substance, as recited in claim 17 , wherein: the environmental effect is temperature.

Claim 24

A method of detecting a substance, as recited in claim 17 , wherein: the second mode is a harmonic of the first mode.

Claim 25

A method of detecting a substance, as recited in claim 17 , wherein: the second mode is a harmonic of another mode.

Claim 28

A method of detecting a substance, as recited in claim 21 , further comprising a plurality of environmental effects is equal to the number of modes.