Abstract: A SAW-based micro-sensor apparatus for simultaneously monitoring acceleration/vibration and temperature utilizing a sensing element configured as a SAW device (e.g., SAW resonator or SAW delay line). The SAW device can be located in different locations on a substrate with respect to a thin piezoelectric diaphragm comprising an inertial mass. The temperature-compensated acceleration/vibration can be measured utilizing a frequency difference between an acceleration sensitive SAW resonator (e.g., SAW-g) and a temperature sensitive SAW resonator (e.g., SAW-T). The temperature can be measured utilizing a frequency shift provided by the SAW-T and a temperature reference SAW resonator (e.g., SAW-R). Similarly, the phase response of different reflectors of the SAW delay line can be utilized to differentially measure the acceleration/vibration and temperature.

Abstract: A SAW based sensor apparatus utilizing semi-synchronous SAW resonator having a single resonance at Bragg frequency with very high quality factor is disclosed. The semi-synchronous SAW resonator includes at least one inter-digital transducer, which generates and receives surface acoustic wave and a number of grating reflectors, which reflect the surface acoustic wave and generate a standing wave between the reflectors, The interdigital transducer and the grating reflectors can be fabricated on a substrate (e.g., quartz) by photolithographic process. The resonance condition is independent of transducer directivity and reflection coefficient per finger. Such a SAW based sensor apparatus having three semi-synchronous SAW resonators can be utilized for measuring pressure and temperature for a wireless tire-pressure monitoring system.

Abstract: The present disclosure relates generally to wireless detection systems. In one illustrative embodiment, a wireless detection system includes a plurality of surface acoustic wave (SAW) sensors, and an electronic reader for interrogating the plurality of SAW sensors. In some instances, each of the surface acoustic wave based sensors includes an integrated sensor coil. The electronic reader may include a plurality of reader coils and a controller. The controller may be configured to interrogate the plurality of surface acoustic wave based sensors using a time division interrogation. In some cases, each of the plurality of reader coils is inductively coupled to only one of the integrated coils of the SAW sensors at any given time.

Abstract: A solar cell includes an organic heterojunction having at least one donor material and at least one acceptor material. The solar cell also includes an inorganic heterojunction having multiple inorganic semiconductor materials. The organic heterojunction and the inorganic heterojunction could absorb light in different portions of a solar spectrum. For example, the organic heterojunction could absorb higher-energy photons, and the inorganic heterojunction could absorb lower-energy photons. The inorganic heterojunction could include a p-type inorganic semiconductor material having a bandgap between one and two electron-volts and an n-type inorganic semiconductor material having a bandgap greater than three electron-volts. An inorganic semiconductor layer could be placed between the organic heterojunction and the inorganic heterojunction. The inorganic semiconductor layer could be configured to collect holes generated by the organic heterojunction and to block electrons generated by the organic heterojunction.

Abstract: An on-chip low baseline drift SAW/LAW chemical sensor array and method of forming the same. A dual SAW delay line includes a common IDT for generating an acoustic wave and a pair of IDT for reception of the acoustic wave. One sensing layer or one reference layer can be deposited in position on each side of the common IDT. An ASIC chip includes on chip dual operational amplifiers and a mixer in order to obtain a differential measurement utilizing a difference being given by the sensing and the reference layers. A 3D technology can be employed in order to connect the sensor array and the ASIC in the same package and thereby form a 3D stack. The chemical sensor array and the ASIC can be configured in different packages and interconnected on the same substrate utilizing 2D technologies. A number of gases can be detected independently, and each gas can be detected differentially, with respect to its associated sensing layer and specific reference layer.

Abstract: An intelligent packaging system utilizing acoustic wave devices includes an electronic module, a SAW ID, various passive SAW sensors and a printed antenna. The passive SAW sensors include a SAW pressure sensor, a SAW temperature sensor and one or more SAW chemical sensors for monitoring physical parameters of a package content. The electronic module generally includes a printed large area distributed electrical circuit, an impedance transformer and a SAW transponder for realizing passive wireless monitoring of the structural integrity of the package. A separate power harvesting antenna and/or a separate dual band antenna can generate radio frequency (RF) power for biasing components associated with the electronic module.

Abstract: A method includes forming multiple trenches in a first wafer, forming a sensor structure on a first surface of a second wafer, and bonding the first wafer and the second wafer. The method also includes etching a second surface of the second wafer to form a sensor diaphragm in the second wafer. The method further includes removing a portion of the first wafer by cutting the first wafer in multiple areas of the first wafer associated with the trenches. A sensor includes a substrate and a surface acoustic wave (SAW) resonator on a first surface of the substrate. The sensor also includes a bonding pad electrically coupled to the SAW resonator and a notch formed in a second surface of the substrate. The sensor further includes a cover separated from the first surface of the substrate by a spacer. The SAW resonator is located between the cover and the substrate.

Abstract: A method includes forming a hole in a first wafer and forming a sensor structure in or on a second wafer. The second wafer includes a piezoelectric material. The method also includes bonding the first wafer and the second wafer, where the sensor structure is located between the wafers. The method further includes forming a sensing layer by depositing material between the wafers through the hole in the first wafer. The sensing layer could be formed by depositing a sensing layer material on the second wafer using direct printing. Also, the hole through the first wafer could be formed using ultrasonic milling, micro-drilling, laser drilling, wet etching, and/or plasma etching. A spacer material could be used to bond the wafers together, such as frit glass paste or an organic adhesive. Trenches could be formed in the first wafer to facilitate easier separation of multiple sensors.

Abstract: A sensor includes a piezoelectric substrate and conductive elements formed in or over the substrate. The sensor also includes a sensing layer formed over the substrate. The sensing layer has one or more properties (such as a mass loading, an electrical property, or a visco-elastic property) that vary based on at least one measurand to be measured by the sensor (such as carbon dioxide). This may affect, for example, a propagation velocity of acoustic waves in the sensor and/or a resonant frequency of the sensor. The sensing layer includes a combination of polyaniline and carbonic anhydrase. The combination of polyaniline and carbonic anhydrase could be formed using an emeraldine base. For instance, an aniline can be dissolved in water to form a mixture, and hydrochloric acid and an oxidant can be added to the mixture. A chemical polymerization of the aniline in the mixture can be performed to form polyanilne.

Abstract: A glass cover wafer is bonded to a quartz SAW using glass frit technology, such that the glass wafer and glass frit formulation provides a thermal coefficient of expansion (TCE) of glass that fits the average TCE of the quartz in two perpendicular directions in a unique package. A dicing technology is used for chip separation. The sensor back side and the shaft are attached with a glass glue that transitions the TCE from the shaft to the quartz without interposing a large amount of the glue.

Abstract: A glass cover wafer is bonded to a quartz SAW using glass frit technology, such that the glass wafer and glass frit formulation provides a thermal coefficient of expansion (TCE) of glass that fits the average TCE of the quartz in two perpendicular directions in a unique package. A dicing technology is used for chip separation. The sensor back side and the shaft are attached with a glass glue that transitions the TCE from the shaft to the quartz without interposing a large amount of the glue.

Abstract: A SAW sensor module can be produced with a true all quartz sensor package (TAQSP) attached to a substrate. The TAQSP has a quartz cover direct quartz bonded to a SAW sensor on a quartz substrate. The TAQSP can be mass produced by direct quartz bonding a quartz cover wafer, having many covers, to a quartz sensor wafer, having many sensors, thereby producing a wafer tandem. The wafer tandem can be further processed because the bond protects the sensors within. Individual sensor packages can be obtained by cutting stripes out of the cover wafer, revealing SAW sensor bonding pads, and then dicing the wafer tandem. A SAW sensor module results when the sensor packages are attached to an antenna bearing substrate and then sealed.

Abstract: A multifunctional multichip system can operate in a passive mode by using at least one antenna to receive electromagnetic energy and using that energy to perform system functions. The system includes a sensor, an impedance matching circuit and an RFID module. The sensor produces a sensor signal containing a measurement. The RFID can produce an identification signal containing identification information. Alternatively, the RFID chip can be used in an addressing mode wherein the system only produces a signal in response to an addressing signal containing addressing information. The addressing signal is received from the electromagnetic field. In either mode, the sensor signal is coupled from the antenna into the electromagnetic field from which a receiver can obtain it. The signal can contain the identification information as well as the measurement. A matching network minimizes the effects of impedance mismatches between the system elements.

Abstract: Improved SAW pressure sensors and manufacturing methods thereof. A SAW wafer including a number of SAW transducers disposed thereon may be provided. A cover wafer may also be provided, with a glass wall situated between the cover wafer and the SAW wafer. The cover wafer may be secured to the SAW wafer such that the glass wall surrounds the SAW transducers. In some instances, the glass wall may define, at least in part, a separation between the cover wafer and the SAW wafer. One or more contours may also be provided between the cover wafer and the SAW wafer such that at least one of the contours surrounds at least one of the SAW transducers when the cover wafer is disposed over and secured relative to the SAW wafer.

Abstract: A sensor packaging system and methodology includes a plastic substrate configured to include a gap for receiving and maintaining an acoustic wave sensor. An antenna can be printed directly on the plastic substrate and connected electrically to the acoustic wave sensor for the transmission and receipt of data from and to the acoustic wave sensor. The antenna can be flip chip mounted to the acoustic wave sensor, which can be implemented, for example, in the context of a Surface Acoustic Wave (SAW) sensor chip. Such a SAW sensor chip can includes a plurality of metal electrodes located on the same surface of the plastic substrate as the SAW sensor chip.

Abstract: A pressure sensor is constructed of a plastic package. The plastic package incorporates in the same material a sensing diaphragm including tensile and compression regions. Deposited on the diaphragm are metal electrodes and a polymer film having piezoresistive properties. The electrodes and/or the polymer film are directly printed onto the plastic package without the use of a mask.

Abstract: A piezoresistive pressure and/or strain sensor micro-machined primarily from plastic and/or glass. In one illustrative embodiment, the piezoresistive pressure sensor is formed on a polymer substrate. A first selectively implanted region is provided in the polymer substrate to create a piezoresistive region in the polymer substrate. A second selectively implanted region is then provided in at least part of the first selectively implanted region to modulate the electrical conductivity of the first selectively implanted region. The illustrative sensor may be selectively implanted with, for example, nitrogen to create the piezoresistive region, and boron to modulate the electrical conductivity of the piezoresistive region. Phosphorus or any other suitable material may also be used to modulate the electrical conductivity of the piezoresistive region, as desired.

Abstract: A vacuum sealed SAW pressure sensor is disclosed herein, which includes a sensing element configured as a SAW device (e.g., SAW resonator or SAW delay line) supported by a thin diaphragm. The substrate material can be implemented as a quartz wafer (i.e., a “base” wafer). The SAW device can be configured on one side of the wafer and the diaphragm etched on the opposite side. A quartz micromachined pressure sensor can thus be realized, which operates based on a variation of the surface wave velocity of a SAW device situated on the thin diaphragm. The SAW sensor is generally sealed in a vacuum and diaphragm sustains the sensor, thereby implementing a sensor on a wafer scale while allowing for a cost reduction per chip.

Abstract: Devices and methods for acoustically measuring temperature and pressure are disclosed. A SAW sensor in accordance with an illustrative embodiment can include an electrode structure adapted to transmit and receive surface acoustic waves along a SAW delay line, temperature sensing means for measuring temperature along a first direction of the SAW delay line, and pressure sensing means for measuring pressure along a second direction of the SAW delay line. The SAW sensor can include an antenna adapted to wirelessly transmit and receive RF signals to and from an electrical interrogator unit that can be used to power the SAW sensor.

Abstract: A quartz sensor method and system are disclosed in which a plurality of SAW sensing resonators can be mechanically simulated for implementation upon a quartz wafer substrate. The quartz wafer substrate can thereafter be appropriately etched to produce a quartz diaphragm from the quartz wafer substrate. A plurality of SAW sensing resonators (e.g., pressure, reference and/or temperature SAW resonators) can then be located upon the quartz wafer substrate, which is based upon the previously mechanically simulated for implementation upon the substrate to thereby produce a quartz sensor package from the quartz wafer substrate.