MAGNETIC SURFACE ACOUSTIC WAVE SENSOR APPARATUS AND METHOD
First Claim
1. A sensor, comprising:
- a magnetic film; and
a surface acoustic wave device upon which said magnetic film is located, said surface acoustic wave device responsive to a magnetic field, wherein said magnetic field changes a conductivity of said magnetic material to generate a frequency shift measurable as a function of said magnetic field, said frequency shift indicative of a physical property detectable by said sensor.
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Accused Products
Abstract
A magnetic sensor that includes a magnetic film deposited on a surface acoustic wave device. The surface acoustic wave device includes an input interdigital transducer and an output interdigital transducer. An RF voltage can be applied at the input interdigital transducer in order to generate acoustic waves, which can travel via the magnetic material to the output interdigital transducer. The application of an external magnetic field alters the conductivity of the magnetic material. Such a change in conductivity attenuates the velocity of the traveling surface acoustic wave and an output frequency due to electro acoustic interaction. The change in the applied magnetic field can be indirectly monitored as a change in output frequency of the SAW device at the output interdigital transducer.
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Citations
20 Claims
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1. A sensor, comprising:
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a magnetic film; and a surface acoustic wave device upon which said magnetic film is located, said surface acoustic wave device responsive to a magnetic field, wherein said magnetic field changes a conductivity of said magnetic material to generate a frequency shift measurable as a function of said magnetic field, said frequency shift indicative of a physical property detectable by said sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A magnetic sensing system, comprising:
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a surface acoustic wave device upon which a magnetic film is located; and an RF transmitter that transmits an RF signal for excitation and interrogation of said surface acoustic wave device, wherein said surface acoustic wave device is responsive to a magnetic field that originates from a magnetic field source, wherein said magnetic field interacts with said magnetic film to change a conductivity of said magnetic film to generate a frequency shift measurable as a function of said magnetic field, said frequency shift indicative of a physical property detectable by said sensor. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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18. A magnetic sensor, comprising:
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a magnetic film; a surface acoustic wave device upon which said magnetic film is located, wherein said surface acoustic wave device comprises an input interdigital transducer and an output interdigital transducer; and a voltage source for applying an RF voltage with respect to said input interdigital transducer in order to generate an acoustic wave that travels via said magnetic film to said output interdigital transducer;
such that an application of a magnetic field changes a conductivity associated with said magnetic material in order to measure a frequency shift as a function of said magnetic field and provide an indication of a physical property detectable by said magnetic sensor. - View Dependent Claims (19, 20)
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Specification