Abstract: A method for sensing at least one level parameter of at least one liquid in a tank. At least one bulk acoustic wave (BAW) sensor is positioned inside the tank. Electrodes of the BAW sensor are at least switchably connected to a positive feedback loop across an amplifier to provide an electronic oscillator. At least one acoustic viscosity measurement is determined from an output of the electronic oscillator, wherein the output of the electronic oscillator is different when the BAW sensor contacts the liquid as compared to when the BAW sensor contacts air. The level parameter is determined from the acoustic viscosity measurement.

Abstract: A coupling device for impedance matching a probe of a guided wave radar (GWR) system. A feed-through is for connecting to a coaxial cable or other transmission line connector that includes an inner conductor which connects to an output of a transceiver and an outer conductor that connects to an outer metal sleeve. A subwavelength coaxial transmission line (CTL) having a length from ?/5 to ?/2 is coupled to the feed-through including an inner conductor connected to the inner conductor of the feed-through and an outer conductor connected to the outer metal sleeve. A mode converter (MC) having a plurality of metal fingers (7) of length 2?±twenty percent is connected to the outer conductor of the subwavelength CTL, where the MC includes a dielectric coating on its inner conductor connected to the inner conductor of the subwavelength CTL.

Abstract: Chemical sensors such as carbon dioxide sensors and methods for making such sensors are disclosed. An example carbon dioxide sensor may include a substrate, with a sensing beam supported by the substrate. The sensing beam may be configured to resonant. A sensing layer may be disposed on the sensing beam, wherein the sensing layer may include an amino group and is configured to sense carbon dioxide. In some instances, a reference beam may also be supported by the substrate, and may be configured to resonant. A reference layer may be disposed on the reference beam, wherein the reference layer may includes an amino group that has been poisoned so that it will be substantially non-sensitive to carbon dioxide.

Abstract: A lead-free, self-corrosion-free electrochemical galvanic oxygen sensor is provided. The preferred sensor includes a container, the container including a lead-free anode, an alkali electrolyte, a carbon platinized with platinum cathode and a nickel wire current collector, wherein the container further includes a diffusion barrier that causes the sensor to operate in the limiting current region.

Abstract: A piezoelectric strain sensor and method thereof for detecting strain, vibration, and/or pressure. The sensor incorporates a sequence of piezoelectric and semiconductor layers in a thin-film transistor structure. The thin-film transistor structure can be configured on a flexible substrate via a low-cost fabrication technique. The piezoelectric layer generates an electric charge resulting in a modulation of a transistor current, which is a measure of external strain. The sensor can be formed as a single gate field-effect piezoelectric sensor and a dual gate field-effect piezoelectric sensor. The semiconductor layer can be configured from a nanowire array resulting in a metal-piezoelectric-nanowire field effect transistor. The single and dual gate field-effect piezoelectric sensor offer increased sensitivity and device control due to the presence of the piezoelectric layer in the transistor structure and low cost manufacturability on large area flexible substrates.

Abstract: A system for detection of stress and deformation in a structural asset, for instance, one of reinforced concrete. An area on the asset may have a structure interface, such as a patch, attached to it with a fastening mechanism which may be a layer of an epoxy or other material, or be items such as screws, bolts, welds, or the like. One or more surface acoustic wave (SAW) strain sensors may be attached to the interface with an adhesive layer of epoxy or other material, or with mechanical items. Stress may be transmitted by the interface to the strain sensors. The sensors may be interrogated with a wire or wireless reader to obtain strain measurements. The measurements may indicate stress and deformations such as bulges and breaks in the asset. The measurements may also be a basis for determining location and extent of the stress and deformations.

Abstract: A differential resonant sensor apparatus and method for detecting relative humidity in an ambient air. The apparatus generally includes a sensing loop, a reference loop and a mixer. A hydrophilic sensing layer can be deposited on a sensing resonant beam and a corresponding hydrophobic reference layer can be deposited on a reference resonant beam for detecting water vapor concentration in the ambient air. The hydrophobic reference layer possesses similar visco-elastic properties as the hydrophilic sensing layer with no water absorption properties. A differential reading electronic circuit may be interconnected with each resonant beam for signal processing. The absorbed humidity with respect to the sensing resonant beam changes the mechanical resonance frequency, which can be detected as a change in the electric resonance frequency of the associated electronic circuit.

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 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 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 resonant nanosensor apparatus associated with a functionalized monolayer for detecting carbon dioxide and a method of forming the same. A wafer including a sensing vibrating beam and a reference vibrating beam may be functionalized with a functional group in order to form a sensing self monolayer. The sensing self assembled monolayer may be configured by bridging oxygen or carbon atoms covalently bonded with respect to the vibrating beams. A liquid solution of hydrochloric acid may then be applied to the sensing self assembled monolayer at the surface of the reference beam by a direct printing process to obtain a reference monolayer. The liquid solution of HCl transforms the functional groups responsible for the carbon dioxide detection into protonated groups, which do not react with carbon dioxide, but possess visco-elastic properties similar to that of the sensing monolayer.

Abstract: Chemical sensors such as carbon dioxide sensors and methods for making such sensors are disclosed. An example carbon dioxide sensor may include a substrate, with a sensing beam supported by the substrate. The sensing beam may be configured to resonant. A sensing layer may be disposed on the sensing beam, wherein the sensing layer may include an amino group and is configured to sense carbon dioxide. In some instances, a reference beam may also be supported by the substrate, and may be configured to resonant. A reference layer may be disposed on the reference beam, wherein the reference layer may includes an amino group that has been poisoned so that it will be substantially non-sensitive to carbon dioxide.

Abstract: A system for detection of stress and deformation in a structural asset, for instance, one of reinforced concrete. An area on the asset may have a structure interface, such as a patch, attached to it with a fastening mechanism which may be a layer of an epoxy or other material, or be items such as screws, bolts, welds, or the like. One or more surface acoustic wave (SAW) strain sensors may be attached to the interface with an adhesive layer of epoxy or other material, or with mechanical items. Stress may be transmitted by the interface to the strain sensors. The sensors may be interrogated with a wire or wireless reader to obtain strain measurements. The measurements may indicate stress and deformations such as bulges and breaks in the asset. The measurements may also be a basis for determining location and extent of the stress and deformations.

Abstract: A differential resonant sensor apparatus and method for detecting relative humidity in an ambient air. The apparatus generally includes a sensing loop, a reference loop and a mixer. A hydrophilic sensing layer can be deposited on a sensing resonant beam and a corresponding hydrophobic reference layer can be deposited on a reference resonant beam for detecting water vapor concentration in the ambient air. The hydrophobic reference layer possesses similar visco-elastic properties as the hydrophilic sensing layer with no water absorption properties. A differential reading electronic circuit may be interconnected with each resonant beam for signal processing. The absorbed humidity with respect to the sensing resonant beam changes the mechanical resonance frequency, which can be detected as a change in the electric resonance frequency of the associated electronic circuit.

Abstract: An apparatus includes a sensor that receives a first electrical signal and provides a second electrical signal in response to the first electrical signal. The second electrical signal is based on at least one parameter monitored by the sensor. The apparatus also includes an antenna that converts first wireless signals into the first electrical signal and that converts the second electrical signal into second wireless signals. The antenna includes a substrate, conductive traces, and conductive interconnects. The conductive traces are formed on first and second surfaces of the substrate. The conductive interconnects couple the conductive traces, and the conductive interconnects and the conductive traces form at least one helical arm of the antenna. The conductive traces could be formed in various ways, such as by etching or direct printing. The conductive interconnects could also be formed in various ways, such as by filling vias in the substrate or direct printing.

Abstract: An all-differential resonant nanosensor apparatus for detecting multiple gasses and method of fabricating the same. The nanosensor apparatus generally includes a sensing loop, a reference loop, and a mixer. A sensing self assembled monolayer (SAM) or an ultrathin solid monolayer may be deposited on a sensing resonant beam associated with the sensing loop to detect the presence of the gas. A reference self assembled monolayer or an ultrathin solid film may be deposited on a reference resonant beam that possess similar visco-elastic properties (e.g., temperature, humidity and aging) as the sensing monolayer with no sensing properties. A differential reading electronic circuit may be interconnected with each resonant beam pair for signal processing. A drift-free frequency signal per each gas may be obtained by subtracting the frequency response from the sensing loop and the reference loop.

Abstract: A resonant nanosensor apparatus associated with a functionalized monolayer for detecting carbon dioxide and a method of forming the same. A wafer including a sensing vibrating beam and a reference vibrating beam may be functionalized with a functional group in order to form a sensing self monolayer. The sensing self assembled monolayer may be configured by bridging oxygen or carbon atoms covalently bonded with respect to the vibrating beams. A liquid solution of hydrochloric acid may then be applied to the sensing self assembled monolayer at the surface of the reference beam by a direct printing process to obtain a reference monolayer. The liquid solution of HCl transforms the functional groups responsible for the carbon dioxide detection into protonated groups, which do not react with carbon dioxide, but possess visco-elastic properties similar to that of the sensing monolayer.

Abstract: A piezoelectric strain sensor and method thereof for detecting strain, vibration, and/or pressure. The sensor incorporates a sequence of piezoelectric and semiconductor layers in a thin-film transistor structure. The thin-film transistor structure can be configured on a flexible substrate via a low-cost fabrication technique. The piezoelectric layer generates an electric charge resulting in a modulation of a transistor current, which is a measure of external strain. The sensor can be formed as a single gate field-effect piezoelectric sensor and a dual gate field-effect piezoelectric sensor. The semiconductor layer can be configured from a nanowire array resulting in a metal-piezoelectric-nanowire field effect transistor. The single and dual gate field-effect piezoelectric sensor offer increased sensitivity and device control due to the presence of the piezoelectric layer in the transistor structure and low cost manufacturability on large area flexible substrates.

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: 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.