Honeywell International Inc.

Mohammed A J Qasimi

James D Cook

Brian John Marsh

Sachin Kumar

Daniel Dixon

Richard Charles Sorenson

Gary R O'Brien

Viorel Avramescu

A wireless and batteryless pressure sensor apparatus comprises of a SAW sensor and an antenna mounted on a printed circuit board. Optionally, and RFID tag in used in combination with the SAW sensor. A sensor antenna and a RFID antenna can be located on the printed circuit board such that the antennas communicate electrically with the sensor and the RFID device. The sensor can be interrogated utilizing a radio frequency, which is used to excite a SAW crystal inside the sensor. The interrogation signal causes the SAW to resonate wherein a resonant frequency changes with the pressure and temperature that is applied to the sensor. An interrogator can receive a return (echo) signal representing a change in SAW sensor properties (e.g., diaphragm change). A printed circuit board can be mounted on a stainless steel port and overpackaged with standard processes for hermetically sealing the sensor, or sensor and RFID device with at least one antenna.

Surface acoustic wave sensor and package

The SAW sensor in a stainless steel button package having a diaphragm and mounted on a threaded port. Package can hermetically seal a sensor and RFID-antenna assemblies from media. Sensor diaphragm is exposable to media. Sensor and RFID antennas communicate electrically with SAW sensor and RFID device, respectively, for sensor measurements and identification. Antennas receive RF interrogation signal from a nearby interrogator/transceiver and send reflected RF signals back to the interrogator unit containing sensor measurement and sensor ID. TRF signal excites a SAW resonator inside the sensor and causes the SAW to resonate wherein resonant frequency changes with pressure and temperature applied to the sensor. Antennas could be printed circuit board antennas, helical antennas, loop antennas, any other commercially available off-the-shelf antennas or a combination of these.

A method and apparatus, wherein a die is attached to a supporting base structure utilizing a rigid bond adhesive for a SAW (Surface Acoustic Wave) sensor. A rigid bond adhesive with a preferably high glass transition temperature (Tg) can be applied directly between the die and the die supporting structure in a pattern to eliminate time dependent gradual stress effects upon SAW sensor. The rigid bond adhesive can then be cured, which results in a high yield strength and a high young's modulus. The supporting base and the die material comprise a same co-efficient of thermal expansion in order to avoid die displacement over temperature.

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Freeport, IL, United States of America

Mohammed A J Qasimi